What should I be for Halloween?!?

I am a 15 year old girl who still loves to trick or treat! I don't like super y costumes but I'm not super conservative either. I have to wear my costume to school so it has to be easy to wear and look good! I dont like buying costumes i prefer to make my own or buy clothing and turn It into a costume.I don't wanna be scary. I really like things with tutus if that helps...any and all ideas welcome!! Thanks! :)