Family help, sorry it's a long story. Help?

I turn 18 in 3 months and want to move out right now, I have a verbally abusive stepfather and mom, I tried to leave one night and they said they will call the cops and send me away to a facility for the rest of my time of being 17… Can they do this? I go to school full time and work enough support myself, I have a family member who said they will let me move in until I graduate or basically whenever I feel like leaving. I have good grades and a very good job, I don’t do any drugs and don’t drink alcohol. My mom says that me and my biological dad have no say in this. My stepfather recently blew up and punched stuff in the house, yelled/cursed at me and at one point told me to get the f*ck out of his house. A few questions I have are.. If I feel like its an unsafe environment, why wouldn’t I have a say in where I go? Am I able to get a restraining order on my stepfather? Can they really send me to a facility until I turn 18? Am I considered “incorrigible” for my actions telling them I hate living there and I’m leaving? It’s always so hostile in that house and I want to leave. I feel like my life would be a lot healthier if I could just go to work, go to school, then go to a place where I can feel relaxed and safe, and don’t have to worry about being yelled at for nothing. -Why did they do this if I sound like i’m a normal responsible person? Because I guess I’m disrespectful to them because I’m not home often so they feel like I avoid them. Well when im at school and work from 8am to 9pm, what do they expect? I spend my weekends with my girlfriend because its my only free time, I don’t relate to anything my mom or stepdad like, we have very different interests, which is why I don’t really feel like killing time on my weekends with them.. Am I in the wrong here or what should I do?!