Last name

I heard from my child's father for the first time in months today. (We actually just ran into eachother at the gas station) he asked me if I was keeping the name we picked out the same, I am but I told him I plan on using my last name, and that maybe we could re-evaluate that issue in a year or so. I have no idea if he is even going to be a stable force in my babies life, I don't want him to grow up hating his last name because his dad wasn't there for him. I guess I just want proof he will be there first. Anyways, he said as soon as we go to court the judge will grant changing his last name because he is the father. Anyone have experience with this? I'm due in eight weeks