How do I prove I'm not a bad person?

I'm only 13 years of age. I have been hared and been called goth since the fifth grade. All I do is wear black. My mom thinks I'm just, I don't know how to explain it-evil? She thinks I'm a devil worshiper or something. I have rings with virgin Mary and GOD and my mom thought they had devils on them. I wear a small am out of eyeliner where 'normal' people usually do and I pluck my eyebrows a little because I am a teenager. I have light brown hair with long hair that's sometimes in my face. I don't know what to do. I'm just emotionally dysfunctional but I'm not evil! Everyones so rude and they don't know the pain I'm going through. I wear black to hide my poor figure because darker clothing makes me look bigger. I'm so big but I barely even eat anymore. I just don't get it. Is there a way for me to get all these people to just, stop? How can I show my mom I'm not really that bad? She yells at me everyday and threatens to hit me across the face. And me and the boy I like that likes me back, I don't want us to be together. I don't want my constant emotions hurting him. I try to smile and laugh and be funny but, I just can't name my state of mind.