my last name or my fiances last name

We've been engaged for almost 2 years. I'd like to be married before the baby gets here and when I told him that he said that ain't gonna happen.. If I give the baby his last name hell have just as much rights to it as I do and he'll have to support it but then again if we split up he'll be able to come get the baby and take it wherever with whoever he chooses. There's so much ups and downs about it all. If I give the baby my last name until we get married then I can change the baby's last name when I change mine. I'm 18 years old and the dad my fiance is 23. I don't have a job right now but after the baby I wanna be a cna. It's what I wanted to do before I got pregnant. We are young. But I will be ready and I will take Care of this baby no matter what. Just need some advice please no rude comments