I don't know what to think

So where's the problem? She was 25 or 26 when he was born. Where's the issue there? Living with your mom at 36, in general, is not inherently a problem.

Look, you have allowed this guy to keep his personal life hidden for this long. Now you arrived at his doorstep to discover things he was not telling you. You don't trust him and he's not into self-disclosure. To my mind this doesn't sound like a relationship made to last.

What does this mean?

Have you never met his son? Have you met him once? I'm unclear as to what you mean here.

not sure what's so odd about not wanting to see someone after you've gone to bed

I'd have seriously freaked out on your head just for that

I'm curious how you define relationship.

you know...texting and email..a real relationship

You said you looked up his address and your friend drove you to his place. When you appeared at his front door unannounced and uninvited, that was probably a bad idea. He might have been married. He might have been cheating on his girlfriend. Who knows. Showing up at his doorstep like that, could have turn out really really bad. If he wanted you to come to his place he would have voluntarily gave you his address and invited you over. You would have been better off asking him if you could come over to his place sometime. Then it would be up to him to say yes or no. It would also be up to him whether or not he wanted you to know where he live. If you are not comfortable not knowing things about him such as where he live, you should tell him.