How old do you have to be for your constitutional rights to take effect?

That depends on what constitutional rights you are talking about. You must be 35 to run for president. You must be 18 to vote. You must be a voter to tell public school administrators how to act. You can protest, but this will just get you into more trouble. I had a mowhawk when I was in High School. All I got was laughed at. Just conform with the rules and you will grow up to be a responsible citizen. The ACLU, American Civil Liberties Union may be able to help, but I doubt it.