I think in theory it would be okay for young adults 15-16 to start having sex, but education is key from both the parents and the school. That's advising, not telling. Telling teenagers what to do often either turns to rebellion or strict adherence.
So in theory, yes it's okay. In actuality, usually not. However, masturbation is a good thing and I would suggest doing that first regardless. I voted it's neither good nor bad.