I don't have a teen girl, yet. But I taught high school, 9th grade...I sat in on our sex education program just to see what was being taught and what the kids were asking about.
Good grief, I thought was was in a college human sexuality class...the things they knew about, had experienced, etc etc
Then just in my interactions with my students...the STDs they were dealing with (including HIV), the miscarriages (in junior high), the student who was due with her child the same week I was due with my son, the students openly having same sex relationships (more lesbian couples...but a lot of experimentation).
PLEASE!! Talk with your daughter about sex and oral sex...and the long term consequences. And YES there is a lot of sneaking around to spend time with boyfriends/girlfriends. So let her know you trust her until she gives you a reason not to trust her and spell out the consequences of breaking your trust. (No more sleep overs, turning off the texting on her phone or no cell phone, etc etc). Be sure to explain how some boys will say anything to have sexual experiences including "I love you"...and explain what true love really is to her.
Sending you a great big hug!! You can do it!!