School counselor is the best way to go! They have a lot of training and will know how to deal with the situation depending on your best interest. If your school doesn't have a counselor, go to a trusted and caring teacher! If you don't have any of those, go to the police. It is scary to talk to an adult that you don't know very well about this stuff, but it is important that you put yourself first if someone is hurting you, even if you don't feel like it is 'severe.' You deserve to feel safe all the time, especially at home!
I understand its scary to think of calling the cops, you feel like you'd just get in trouble for telling, but it could get worse. Don't wait for that to happen. If your too uncertain to do that, then next time it happens, dont be afraid to defend yourself by backing away or blocking/dodging. If she attacks you or something crazy, then DEFINITELY call the cops right there.