17 and pregnant. Want to move out.

I'll be 18 when my baby is 5 months old. I want to move out because my mother has not been a mother to me my whole life. She was abusive until I was around 10. I watched her beat my brothers and sisiters heads into the wall until they were bleeding. My brother chased me with a butcher knife, literally trying to kill me when I was 6 and she watched and laughed. When I was 6 months old he caught me on fire and hit me in the head with a hammer, I almost died. She has said to me many times she only wants me because of all the child support she gets. My brother lives there and he's a heavy drug user who becomes extremely violent at random times. She knows this and still says "Oh he wont hurt you." I do not want my baby around that. Even when I am there, I don't eat because she literally goes shopping every few months and only buys food for her. I get cookies or chips. That's it, yay! Sarcasm. We don't talk. Never once since I can remember has she hugged me, asked if I was okay, or even had a conversation with me. When I was 14 U was raped by my older brother who was 27, married and had a child. She didn't seek help for me. She didn't ask if I was okay. She wasn't there when I woke up at night screaming and crying or when I got taken out of school and put in digital because being around males caused panic attacks daily. Or when I tried to kill myself 3 times. She's careless. Children services were called on her over 17 times in one school year. Yet nothing happened. 
I stay with my dad 90% of the time. While he's more fit to live with, he makes me feel uncomfortable. It was his son who raped me and he tells me to this day I'm lying. He pretends like it didn't happen. His girlfriend moved in and she's horrible. She doesn't pay bills or have a job. She talks him into paying hundreds of dollars on things she wants when he doesn't have the money to spend. She has her grandkids over all the time where she is rude and mean to them. We also have a puppy who she kicks accross the floor, and keeps him in a cage for days. I have to take care of him and when I do she yells at me. My dad follows her and tells me to get over it. She also tells me i'll be a horrible mother and they both said I am not allowed here when the baby is born and they don't want to be in our lives. 
My fiance is in the military and makes enough to support all 3 of us, and I also have a job. We can live on our own and be well off. I am in control of my schooling as my mom isn't involved. (They allow minors to enroll themselves)  I cannot raise my baby there but Ohio does not allow emancipation on Minors without being married or joining the military. Which I plan to do both but you need parental consent. I am mature enough ro do this on my own. We both are. But I need advice because my baby cannot be in that enviornment. We used protection by the way! But, we had discussed the what ifs beforehand just in case and we had a plan. Any advice? 
I have tried to talk to both my parents but they are just horrible and wont listen. Children services also does nothing. I called them and they said thats not their concern and they cant help.