How do I encourage my sister to develop her OWN personality traits rather than adopting mine?

I reworded this question many times because the earlier version of this question was asked when I was still very angry at her. Bad idea lol ;) Anyhoo, you guys know how it is when people copy you. You know how extremely irritating it is- especially when they try to p it off as their own idea. I know I really should be flattered and all that, but this copying is becoming a real hindrance on my life. Any suggestions?