Losing it

I'm 15 and going into my sophomore year of high school. A lot of girls at my school are starting to have sex, and I mean a lot. When is the right time to lose your virginity? Are all the other girls starting too early, or am I too late? I feel like I'm expected to start having sex soon, and there's this guy who made it very clear he would hookup with me if I was into it. I've taken health class and I know all about birth control, pregnancy, ect. I just don't know when I should be looking to have sex. Help?