That's why it is given then. It needs to be given before the girls become sexually active ---> before they could be infected. It won't work if you give it to them later. And if you had a daughter and you never let her have the vaccine, what would you say to her if, in her 30's, she develops a cancer that could have been prevented.
I understand that it needs to be given before she is sexually active. But why not wait until she is 16?
Or if you know your child is not active at that point, then 18. I would really prefer that we wait until 18 and my daughter could figure out what she wants to do on her own.