Try it for a half year or so, then see if it works out. If you both really know each other well and you love him, separation from family is normal, friends stay friends, and you'll get together when you want to, as they'll be facing the same thing.
I don't know if he's just not a man that likes to throw around promises when he's not sure of something yet, or is not ready for marriage. If it's the second case, then considering the age difference you should understand that his traits and personality is much more developed and is more stable, that means that changing it is almost impossible, as he might even consider his age a superior factor when deciding something for the both of you. Can't really say much from what you've told.
Love for a 20yo is actually just having someone care about him, being close and understanding. As long as he gives you everything you want, he's everything you need. I can see that he hadn't tripped in doing so, so your attraction to him remains strong, just don't let that overtake your mind.