It took me until after I got out of college to realize that I was not only very smart, but quite the hottie (not hot anymore, tho.).
Girls can really do a lot of damage to other girls. But going to classes to learn about it? It's just a part of life. If the school administrators would show some stones, they could stop a lot of it. But this is just human nature. The feminists have succeeded in feminizing boys; what is it they're doing here with the girls?
Hell, it doesn't stop at HS graduation. I have met many, many bitchy women while in the workplace. Women, in general, are simply nasty to other women --- and, age doesn't matter.