Had similar incident recently.. met an awesome girl that is 2 years younger than myself, we hit it off great and then short while after she left her boyfriend(went out +-16months) and wanted to get in relationship with me.. told her lets take it slow because of the ex and get to know each other first, we hardly know each other but the attraction was there! (Wanted to make really sure because perhaps she can do the same to me when new guy comes along and few other serious reasons)
Very very long story short, I took it too slow for her, she went back to the ex(who I met and could understand why she left him, she's a 10 and he a 4 - looks like the the 5th teletubby) and basically crushed me in the process while I've played it as it should have been..
Lesson learned: Never make impulse decisions, no matter how good you hit it off etc, there's a reason you need to check things out first! Oh and also to stay away from crazies!
Good luck with your choices and decisions!