How can I convince my boyfriend to marry me?

I’m 5 months pregnant, and I really want us all to be a family and share the same last name, and live together, raise the baby together…I don’t think marriage was in his plans right now, Mostly because he’s leaving for the military soon and he’s quite young. Any advice? I don’t want to force him, I just want him to realize that it wouldn’t be a bad thing.