Maybe this is a chance for you to learn how to finally go through a relationship. Not all relationships end in heartbreak; some are actually mutual heartbreaks. Of course, there will be the leftover feelings to deal with, but still. You haven't even gotten there yet. You just gotta remember to live for today. I mean, what if she leaves and you never get the chance to be in a relationship with her?
It is better to love than to never have loved at all. 
Think about it, and decide by yourself whether you really want to pursue this relationship. Try to look at yourself and measure how much you really like this girl.