The vaccine is given to all girls coming up to sexuall maturity. Being sexually active is not one of the questions asked.
What I would say is do not lie to your mother and to be frank with her from the beginning. There is one way to avoid all the worry about cancer of the cervix, always use condoms, and when you are called for a cervical smear you attend. But the vaccine is given in x 3 doses in your arm. Hope this is helpful advice take great care and good luck