The centre is part refuge, part meeting place. She is part tutor and part mentor to her visitors. But for the Taliban, she is all irritant: the insurgents have said they will kill her if they catch her.
If the 52-year-old is worried, she doesn't show it; instead, she regales those who visit her with stories about the women who have come to her, the problems they have, and how she has tried to solve them. She is, in every sense, the godmother of Gereshk – a symbol of how things have changed in the last decade, and how far they have to go in a country where women are very much second-class citizens.
Their treatment under the Taliban was one of the justifications used for British troops remaining in the country following the 2001 invasion, and since then a host of international and home-grown aid agencies have been working to improve women's standing. It is one of the priorities for the UK-led Provincial Reconstruction Team (PRT).
There have been gains, notably in education, and in Helmand there are striking examples of women breaking out and trying to establish themselves in different professions, including within the Afghan security forces.
There are 27 female police officers in the province now, and though most of them are restricted to doing body-search duty, a handful have progressed to detective level, and they are lobbying for firearms and driving training.
Most don't dare tell their families what they are doing, but Corporal Bibi Gull is not one of them. The 28-year-old joined the Afghan Uniformed Police (AUP) in 2009 despite death threats.
"There was a lot of Taliban around and some of my family did not want me to join," she said. "Some of my relatives wanted me killed, but I arrested one of them and he was put in jail. At the beginning I was scared. Now I am not scared. I tell everyone what I am doing. I want to help women in Afghanistan."
Another woman, a private in the police, told the Guardian her husband was the only person who knew where she worked.
In another age, the one before the Taliban, she had been a student at university in Kabul studying journalism. Now, like every female police officer, she has to wear a full burqa at work, and lives in fear that someone might recognise her when she in on duty. Despite the dangers, she perseveres.
"I would like to wear a uniform and be like other police officers. But that is not possible at the moment. My husband gave me permission to join the police, but he is the only one who knows what I am doing. I tell everyone that I am teaching at a local school.
"My brother doesn't know what I am doing. But the most important thing is that my brother-in-law does not find out. He would be very angry with me. All the men in the family would be saying you should not be doing this, you should be looking after the children at home. They do not even think I should be a teacher. If they found out they would beat me."
Shelley Groves, who works for the UK's Ministry of Defence police and is mentoring female officers for the PRT, described the new recruits as "amazing, inspiring and very brave".
"Women want to do this, but they are risking their lives if they join up. We have some very strong women that are prepared to get out there."
The Afghan National Police (ANP) has launched a recruitment drive for educated young women. Groves, who leaves next March, is trying to train a local to replace her so that this kind of work can continue.
"I would like to see female officers all over Helmand," said Groves. "But there are so many different areas and so many different cultures, and there is no chance of getting through in those areas where there are Taliban."
In the provincial capital, Lashkar Gah, there is a women's radio station called Muska, which was set up by Roma Muhammadi, an enterprising 22-year-old. Muska – which means "smile" in Pashto – has a staff of eight, including producers and journalists, and they are all women. Muhammadi, who only started school after the Taliban left, has ambitions to make Muska a national network.
"At the beginning it was a struggle, it was very difficult," she said. "The reaction of the men was very bad. That changed when they realised our programmes were not anti-men, pitting men against women. I plan to attract more people and more staff. My first focus is Helmand, but I would like to have radio all over Afghanistan."
At the other end of the spectrum, back at the women's centre in Gereshk, Sherzad sees the difficulties that women face on a daily basis.
"The day before yesterday a girl came here," she said. "She escaped her family and fled because they wanted her to marry. They were forcing her to marry because her brother had killed a member of another family, and that family wanted money or a girl in return.
"When she said she didn't want to marry she was beaten up and abused. She is 14."
Sherzad said the teenager has been staying with her because she has nowhere else to go. "I don't want her attacked again. I don't want the ANP to get involved at this stage. I want to meet with her family and try to sort it out.
"If it is beyond my powers, I will go to the ANP or the district governor. I will tell the authorities, so that everyone knows what is going on. Most women will come to me before they go to the police. I may get six or seven cases a week, it depends."
It is a measure of Sherzad's reputation that people respect her as a fixer, even though, as a woman, she has no way of enforcing any of her proclamations. She has the status of an elder, and that has not pleased the Taliban.
"A couple of years ago there was a family living in a rural area. They had a land issue and I got them to sign a document to solve the problem.
"Four hours later I got a call from a commander of the insurgents. He said the decision I had made was perfect under Sharia law. He said the way I had dealt with the case was right. And then he said: 'If I catch you, I will kill you.'"
On another occasion, the husband of a woman she had helped planted a roadside bomb outside her house. "It was frightening, but luckily it did not hurt anyone."
Sherzad does not believe the Taliban will come back to power here, but she is under no illusions about the position of women in the communities around her.
"Women are still second-class citizens in Afghanistan. In the bazaar, things are getting better for women very slowly. You can see them around and the young girls are going to school. But in the rural areas it is the same as it was 20 years ago. They are doing the harvesting and getting the wood for the fire."
There is no official women's shelter in Helmand because it was feared the Taliban would make it a prime target and put the women in even graver danger.
So with no other means of protecting them, women have to be put in jail for their own safety. This is still a country where running away from your family is considered a criminal offence, and a man who murders his wife can be freed the next day if he pays 200,000 afghanis – approximately £3,000.
Sherzad runs workshops at her centre and gives lessons on human rights. But she relies on handouts to keep the building open, and needs donors to support her work.
That work will be difficult even if the Taliban remain sidelined. Like many of Afghanistan's southern provinces, Helmand is Pashtun, and women here have never had equal human rights. There are cultures that will take generations to challenge.
One official cautioned it would be wrong to assume that the issues women face are just insurgent-related. Far too many men have yet to understand it is not a natural right to "rape and beat a woman". The problems are so entrenched, the official said, that it was extremely difficult to target.
The government in Kabul has made some efforts to change the culture; it set up a ministry of women's affairs, and the country has a constitution that enshrines women's rights to equality, work and education. In 2001, only 5,000 girls were enrolled in schools across the country – by last year that figure had shot up to 2.7 million.
There are 69 female members of parliament, making up more than a quarter of the total (27.7%) – a higher proportion than in France, Canada and the UK – and in 2009, the Law on Elimination of Violence Against Women was passed.
However top-down legislation doesn't work well in Afghanistan's highly patriarchal, tribal society; what is said and done at local level remains paramount. The new laws are not applied evenly, or policed strictly – which is hardly a surprise given the views of President Karzai's justice minister, Habibullah Ghalib.
In June, at a conference on women's rights, he described shelters for abused women as dens of immorality and prostitution. A week later, he was forced to apologise.
Blaming the precarious security in some provinces, Afghanistan's Independent Human Rights Commission last month reported an increase of violence against women, saying that in the last three months there had been "58 cases of violence aimed at murder or [which] led to murder, most of them honour killing or killing after rape.
The report concluded: "This figure … indicated that women are in danger in different parts of the country due to lack of security, lack of government control, excessive emotional and family violence or presence of armed forces and Taliban."
And there are broader concerns that women's rights will become a negotiating tool in any forthcoming discussions with the Taliban. Oxfam has warned that women "now live in fear that if the Taliban is given a share of power then life will become miserable again."
Women, it seems, have most to lose once Nato's International Security Assistance Force (Isaf) has gone.
"The women living here are quite happy to have Isaf around," said one of the female police officers. "The girls are going to school again.
"We don't want the old tribal wars to come back. It has become more peaceful, especially in the bazaar. We don't want to go back to the Taliban days when Isaf goes."