Did I do the right thing telling him?

Well I'm 19 and I can tell you I'd put allot of effort into a relationship no matter what I'm doing, school and or work. Age doesn't always determine a maturity level, especially at a 3 year difference, for all we know you could be just as immature. Only you can decide if you think he is immature or young minded by the way he carry's himself. I think if you like him you should apologize, admit you both made mistakes and you're ready to accept yours. Then take it from there, if not, move on. It's up to you really, if he doesn't accept, there isn't much more you can do but try.