PA mother

Does anyone know the rights of a single Pennsylvanian mother who lives with her parents? I'll be 21 in December. I'm on my parents insurance and they're paying for the babys insurance (chip) also. Im due at the end of August and I honestly don't think my boyfriend and i will make it as a couple. I'm going to school to be a teacher and I work part time in a daycare. He lives with his nan and has a job but doesn't make enough to even support himself and he doesn't get help from his family. He also has a history of psychological outburst and even had to be hospitalized for it. He is on medication but if he forgets a few pills, he's pretty much homicidal/suicidal and there is no way to reason with him. I'm afraid he'd hurt the baby. We will combine our last names and his name will be on the birth certificate. What are the chances of me getting full custody and him only getting visitation?