So I really like this girl...

as Russ said, play down a level and don't be so serious. Some people take a while before realization or definate decisions sink in so don't force it. Unless you're absolutely persistent to date her on the serious level in being togeather forever etc, then I have no real advice on that. Plus, look on the brighter side, walking out of a serious relationship is very derastic and may hold the chance that you two cannot face each other the same way as you two have before dating (eh, speaking out of personal experience -__-") but at least if it's more of a casual dating, i've seen alot of people still remain reallyl good friends if one figures out themselves and ends the dating relationship.

Jam it back in, in the dark.