boyfriend problems

k-train
my boyfriend wants a baby and he wants one bad. he is going into the army and i get why he wants one. i am trying to talk him out of it and he keeps pushing and pushing and pushing me to try for him. there is 4 years between us and i am still in high school unlike him. i mean i wants a baby but not now and i don't know how to break it to him and not have him upset. i just need help and soon