Is my older brother abusing me?

Ohhh hell no. A sister putting her hands on you is one thing... hit the ****** backk... but this is your older brother who should be there & look out for his younger sister. You need to tell your parents that this is getting out of hand. You can contact the police, or join therapy. But from the looks of it, hes the one who needs therapy. Sweetie, if your flinching everytime the guy passes near you, this is serious. You can grow up thinking its okay to hit anyone, and theres no reason whatsoever for the need to put your hands on anyone. Tell a friend, or better yet, tell a teacher.