I say wear it, but make sure you look your best - it's important that everyone understands you are wearing it for the right reasons, not just to be rebellious.

Wear it with confidence - bullies don't know what to do about confidence .. usually because they don't have much of it themselves. Ignore the other kids unless it ever descends into threats. If they threaten you, involve the administration. If they wont do anything, involve the police.

As to the teachers insulting you - I would report them immediately. That is highly uncalled for and extremely unproffessional. If the principal won't address the issue, climb the food chain until you find someone that will.

This is not something I would get lawyers involved in. That never really ends well for anyone. You should be able to sort it out.