How do you know if a guy is your boyfriend (weird, I know!)?

I know this may sound INSANE and stupid to ask, but I am seriously confused. I am seventeen and this guy and I have been going out for about two months now. He has even gone so far as to mention marriage, and has told me that I am wonderful and amazing. He also told me that he wants me to meet his mom. The only thing is, he has not mentioned a relationship. Is that something a guy will automatically ume after you have gone out for a while? Please pardon my ignorance, but this is actually the first relationship for the both of us, so we are pretty shy and confused as it is. Opinions?