Confused

My boyfriend and I have been together for almost two years, and we were friends before we started dating. He was very against having children, but lately he has been saying things like if it happened he wouldn't be mad, and he is ready, and so on and so forth. We have had two miscarriages, both were a surprise as I was on birth control. Now however we just track my cycle to prevent pregnancy. I'm scared that a surprise will come along and that he will find out he isn't really ready. We are both only 19! Can anyone help me out here? How should I respond? I want to keep an open mind but I don't want to rush things!