well, almost 17. not that it makes a difference to my maturity or whatever but birthdays are awesome!
i didnt have anything to do with sex between me being raped (early childhood) and my boyfriend. when i met him he swore he was completely uninterested in sex (which i admit was a bit suspicious but oh well). since i was 'traumatised' when i was younger i struggled (and still do) with anything sexual. long ago i made the decision to not have sex until i was married and my boyfriend has accepted that. unfortunately though many teens are exposed to sex and are very tempted by it.
kids our age make a lot of jokes about it and a lot of the guys pressure girls into it, and some girls willingly do it (boost self confidence, be 'liked', etc). i go to a pretty sheltered religious school but were still exposed to sex quite a lot; media (tv, music, movies, magazines), other students around us, parents, teachers etc etc.
the simple fact is that teenagers are hormonal, rebellious, young, stupid and think we know everything.
id suggest that when your daughter is old enough you should make sure shes able to be open with you. dont just tell her that sex is the worst thing she could do and that youd hate her if she did it or whatever. the unfortunate reality is that its up to the teenager now and the general population (statistics show, apparently) make the wrong choice. so just make sure that if she ever gets herself into a bad situation she can talk to you about it. try to show her that sex is meant for older people and that her virginity is quite a special thing about her and she will value it when shes older because men (at least the nice ones) prefer girls who have had very little sexual partners. i dont know... i think itd be pretty hard as a mother to protect her child from the things in the world, but just let her know shes got a mum who cares because sometimes that can prevent kids thinking that to get people to love them they have to sleep with people.
and its not all that teens do

lots of teenagers are focused on friendships, schoolwork, sport etc. i and a lot of my friends are, especially being in the 2nd last year of college.
my boyfriend and i have found much healthier alternatives to sex. we do all the teen things. were in a band and take school work pretty seriously. we have fun but were pretty obedient kids.
i hope that helped although i dont think you actually asked for any advice so once again, probably just wasting everyones time =)
good luck with your little girl