I have 2 teenage daughters, well one is almost 21 this month. My opinion is that she needs to get new friends, and it is nobody else's business if she is or not a virgin, her friends are just stupid bi...s that want to hurt her.
My experience with my now adult daughter was a totally different. When she was almost 17 and a senior in HS I tried to get her on the pill before going to College, since I wanted her to be ready for anything that could happened, and she REFUSED, there was nothing I said or the dr. said that would changed her mind, she told me and I quote "I have no boyfriend, I am having any sex and I do not need them until I am ready". Now she is 21 with an steady boyfriend and on the pill, she did it on her terms at her own time and I am happy with her decision. Now my 16 years old is a Jr in HS, her situation is a little different, she went thru an abuse by a teacher at a young age and she is not into sex at all, she had a boyfriend last year and she told him plain a simple, I will not have sex with you until and when I am ready, don't ask and if you do not like it then bye. I will put her on the pill when she is ready for it, she knows she can come an tell me she wants to go on them and I will not invade her privacy, her friends are good and she actually distance herself from anyone that is trying to bully her. She takes no crap from anyone. But then not may people knows what she went thru and she is a happy teenager.
Your daughter needs to get her mind set that it is her life, her decision and the Hell with everyone else, if they stop talking to her because of that, then they were never her friends, period. Tell your 16 years old daughter to be her beautiful self, to believe on herself and to do what she wants when she wants it and NO because of some bullies that just want to cause trouble. It is not anybody else business if she is a virgin or not, it is her decision of when, how and with whom she loose it to. She is perfect just by being her usual self. And when she goes on the pill is because she feels that she is ready for that next step. Good luck