Co parenting with someone you don’t know that well

I recently found out I’m pregnant by a guy I’ve known for awhile but we are not in a serious relationship. We dated a little when I was 19 and just randomly hooked up again now that I’m 27. My first reaction was to terminate the child but he is very supportive of me keeping it. I’m just really worried because I never wanted to be an only child. Does anyone have any advice on a situation like this/co parenting? I want to have a final twlk with him about expectations before I make a decision but its just so much to think of 😩