You are right...teens must make their own choices...you just have to hope that they are good choices. Having sex as a teen is a BAD choice...teens are not emotionally ready for it.
When I was a teen, my mom took the opportunity to talk to us while we were riding in the car...we were a captive audience...usually a private talk...she would invite just one of us at a time to go to the store, or run an errand with us...we always thought, "oh boy, here comes the lecture"...but actually, I really enjoyed the one-on-one time. My mom told us all multiple times..."I don't want you having sex with your boyfriend until you are married. If you choose to go against my wishes, please use a condom and foam, so you won't end up pregnant"...
We were never offered birth control pills as teens. And we all managed to grow up without getting pregnant until after we were married.
You can't go out on the dates with your daughter...well, you could, but she probably wouldn't be asked out much...LOL That is when it is up to her to make the right choices. She has to have the courage and confidence in herself to say NO...if the boy won't "love" her without sex, then he's not worth having as a boyfriend...BUT sometimes, it is the girl pressuring the boy...you just never know...and you'd be surprised what can be done in the back seat of a car!! Your daughter needs to know ahead of time "how far" she is willing to go...set limits on her behavior...and if the limits are about to be crossed, she has to be the one to stop it...
It is wonderful that you have such open communication with your daughter...you've done well...many teens will shut their parents out...
We have three boys...my husband has had "the talk" with them...same thing...take them for a drive, and privately talk...explain about making right choices...self-control...and condoms...on a regular basis...plus, I'm not afraid to talk to them either...but I think it is a little embarrassing for them to discuss "male" issues with MOM...they prefer to talk about that stuff with DAD. We keep the conversations age-appropriate...our 10 year old is too young to know much about sex, beyond the mechanics of it...we have books to help explain that...and we gradually add more information, as they ask...
It's pretty hard for them NOT to ask, when erectile dysfunction pills are advertised during "family time" TV, and commercials say words like "semen", and talk about "periods"...our 10 year old picks up on all of it...and he is asking the questions...and he gets matter-of-fact answers...short and concise for now...he'll get "the talk" when he is ready.
I've probably written much more than you want to read...good luck with your daughter...I hope she makes the right choices from now on...
Becky