Yeah... chat rooms. My old friend almost commited suicide because of a chat room boy. and lies... gah i'm a good liar... but its not good to be a liar, love has a progression, after enough time, its like a bomb, concussing through you. you can't stop, change, halt, or derail it.
You should have just told him you were fifteen. And if he really had feelings for you and you for him then he probably would have waited a while longer.
If you would have just told him the truth during your arguement, then maybe y'all could at least be friends.
Unfortunately there is really no advice I can give you, other than now you know one lie can ruin everything.
I'm sorry though, it couldn't have been easy. But don't ever think you aren't worthy enough for someone, because that's up to them, not you.