Petition to have different colored highlights in PC Middle School

We can't have freedom of expression at this school! Freedom to put different colored highlights and lowlights in our hair. Why not? Other than 'the rules say no,' what's their excuse? Do they have an ACTUAL reason? No one has told us it. We're tired of not having freedom of expression. VERY tired of it. We're going to try and convince the school to change the rules.