Why does every youth want to bully me?

I don't know but there's something I noticed about myself and it's that male and female youths no matter what ethnicity always bully and start fights with me for no reason. And whenever I report them, they call me a snitch and begin to call people and behave like gangs around me. I remember when I was in my country before I came to the United States. I used to have friends in school and no one ever bullied me in my schools. And everyone at my school knew me. But then I came to New York and some black and Hispanic males and females began to whisper things about me to people but I ignored them. They would come and point at me in the hallways and when I slipped and fell, they would all burst out laughing at me. They kept talking about my mother in front of me. Then all the black and Hispanic females ganged up on me and kept cursing at me and slamming lockers in my face. At my church the youths don't talk to me and they ignore me all the time. They also try to control me and intimidate me. I've came to wonder why it is that the adults don't treat me this way? I'm a 21 year old female and the black females around my neighborhood where I live keep giving me dirty looks and when I'm walking alone minding my own business they come and walk by me and start asking me why the hell I'm looking at them. Then they roll their eyes at me. And if I ask them if they have the key to the door, they give me attitude and have some aura as if they want to fight me. I'm scared of them because they hang out in groups and can do something terrible to me. God knows I'm innocent and I haven't done anything so I don't deserve to be treated this way. Then they always come and walk with their boyfriends and girlfriends in front of me laughing at me and calling me single. That's why I never go outside.