The mutilation occurred not in Africa, where the practice is most prevalent, but in India where a small Muslim sub-sect known as the Dawoodi Bohra continues to believe that the removal of the clitoris is the will of God.
?We claim to be modern and different from other Muslim sects. We are different but not modern,? Bano, a 21-year-old law graduate who is angry about what was done to her.
She vividly remembers the moment in the party when the aunt pounced with a razor blade and a pack of cotton wool.
While the sect bars other Muslims from its mosques, it sees itself as more liberal, treating men and women equally in matters of education and marriage.
The community?s insistence on ?Khatna? (the excision of the clitoris) also sets it apart from others on the subcontinent.
For generations, few women in the tightly-knit community have spoken out in opposition, fearing that to air their grievances would be seen as an act of revolt frowned upon by their elders.
But an online campaign is now encouraging them to join hands to bury the custom.
The anti-Khatna movement gained momentum after Tasneem, a Bohra woman who goes by one name, posted an online petition at the social action platform Change.org in November last year.
She requested their religious leader, the 101-year-old Syedna Mohammed Burhanuddin, ban female genital mutilation, the consequences of which afflict 140 million women worldwide according to the World Health Organisation.
Syedna Mohammed Burhanuddin is the 52nd Dai-al Mutalaq (absolute missionary) of the community and has sole authority to decide on all spiritual and temporal matters.
Every member of the sect takes an oath of allegiance to the leader, who lives in western city of Mumbai.
When contacted by AFP, Burhanuddin?s spokesman, Qureshi Raghib, ruled out any change and said he had no interest in talking about the issue.
?I have heard about the online campaign but Bohra women should understand that our religion advocates the procedure and they should follow it without any argument,? he said.
A gathering protest
But over 1,600 Bohra Muslim women have since signed the online petition.
Many describe the pain they experienced after the procedure and urge their leader to impose a ban.
?The main motive behind Khatna is that women should never enjoy sexual intercourse. We are supposed to be like dolls for men,? 34-year-old Tabassum Murtaza, who lives in the western city of Surat, told AFP by telephone.
The World Health Organisation has campaigned against the practice, saying it exposes millions of girls to dangers ranging from infections, hemorrhaging, complicated child-birth, or hepatitis from unsterilised tools.
In the Middle East, it is still practised in Yemen, Saudi Arabia, Iraq, Jordan and Syria.
?It is an atrocity committed under the cloak of religion,? says Murtaza, who along with her husband was asked to leave their family home when they refused to get their daughter circumcised.
?My mother-in-law said there was no room for religious disobedience and we should move out if we cannot respect the custom,? she explained. ?It is better to live on the street than humiliate your daughter?s body.?
Asghar Ali Engineer, a Bohra Muslim and expert on Islamic jurisprudence, has known the dangers of fighting for reform.
He has authored over 40 books proposing changes, particularly around the status of women, and has been attacked by hardliners inside a mosque in Egypt and had his house trashed by opponents.
While both France and the United States have laws enabling the prosecution of immigrants who perform female circumcisions, the practice remains legal in India and Engineer expects this to remain the case.
?Female circumcision is clearly a violation of human rights, the Indian government refuses to recognise it as a crime because the practice has full-fledged religious backing,? he said.
?No government has the courage to touch a religious issue in India even if the practice is a crime against humanity.?
He says many fathers are simply unaware of the damage they are doing by following the custom.
?I prevented my wife from getting our daughters circumcised but in many cases even fathers are not aware of the pain their daughters experience,? he says.