Sister copying me help please?

Copying is the highest form of flattery. Ignore it or she will carry on copying you on purpose just to annoy you if she knows it winds you up. Sounds like you rise to the bait too much - she MADE you bleach your hair?! You were the one to do it! Just tell her you feel sorry for her that she has no originality of thought and that you regard it as a compliment that she has to get her inspiration from you...she will soon get fed up with it!