I went to a catholic highschool, and they were pretty tolerant about what people did (granted, it was also a no uniforms school). There was one girl I can remember who dyed her hair a different color on a monthly basis (I can still remember the dayglo green month *lol*), and at least one wiccan student. I do think that at our school, visible non-ear piercings had to be removed during school... unless they had religious significance.
Anyway, if nothing else, your hair is a shade of RED, right? Red, even if it's incredibly intense, is a natural color... it's -technicallly- possible that someone could naturally have hair that bright (i'm visualising a boy in my highschool who had extreme natural red hair... to the point that it just about glowed). What would they do if someone enrolled with bright hair? Refuse to teach them? That's discrimination... most places of work can't even do anything as long as it's a 'natural' color... so anything in the red-orange-brown-black-blonde spectrum should be acceptable. Personally, I'm confused about how EXACTLY your haircolor effects your ability to learn, or that of those around you. Since it DOESN'T, I don't think it's any of your principal's business what color your hair is or how many piercings you have. (of course, I don't think it's a school's business how you dress either, but details)
I love schools that try to turn everyone into little robots... especially when it's having UNIQUE skills that will help land you a decent job later on :P
various cornsnakes, 0.1 black pine snake, 1.0 uromastyx geyri, etc.
"The only thing worse than a human who had no respect for other animals was a human who assumed all other animals thought and felt just like he did." --Julia Ecklar, "ReGenesis"