Adoption? Or not? I'm only 19.

I am 6 weeks pregnant. My boyfriend and I were strictly adoption for about the first week we knew I was pregnant. Now after my first appointment he approached me on keeping the baby. Which I completely agreed with. But things have came up and the devil has basically slipped back into his life. I've told my mom I was pregnant. And she just keeps asking me what I wanna do. I know adoption would probably give the baby the best life possible but why can't I try? I'm stuck between the two and I need to start making decision now and preparing for this baby since I'm only 19 and I don't want to push my baby off on anyone else if I keep him/her. Any advice on this? Please!