I'm 16 and have dated twice, one lasting about 5 months when I was 13-14 and another 2 months when I was fifteen. I have friends who are 18 and have never dated, and others who are 17, have dated over 5 times and have been having sex for over a year. What's normal or average varies depending on the environment too. At my last school, which was a very small (under 200 students all up), and many relationships happened between students at the school, my two seemed like quite a bit. But I have friends at much larger public schools who've had 3-5 relationships at the same age and that isn't out of the norm for them.