Not that it's a huge difference, but Middle Schoolers are only from like 10 minimum to like 14 max. That's it for Middle Schooler's ages.
We all know what happens to some when they get into High School, right? There's always those girls that go nuts (no pun intended

) and are very sexually active. I know for a fact that boys do it too. This is where you get yourself into real trouble too. If you think about it, a lot of the girls that are more "loose" in High School STARTED when they were younger and just progressed quicker than their classmates. It happens. So again, does the school step in to curb that early or do they let nature take its course?