i'm not high-school young but consider myself to be pretty young.
i'm 20 years old, 3rd year of university, and sly. i was experiencing MPB and just got rid of the hair.
at first having hair was a big deal to me, and the idea of losing hair was very troubling, and it affected my life.
by the time i shaved my head, i had accepted the fact that i was losing my hair and was fine with being 100% bald for the rest of my life. i know for a lot of people, this transition is a lot harder, but for some reason i didn't find it all that hard.
i'm not entirely sure if you're losing your hair or not. if you aren't, then maybe it's best to wait until you're done high school, when you are old enough to make decisions and stand by them (not saying you can't now, but people will take your age into consideration right now)
so, really.
just give'r.
if you feel comfortable enough to shave your head, do it.
if you're uncomfortable with the reactions at your age, just wait a while.