Would this be a good Idea? What should I say?

Yeah I think its a good idea, and kudos for wanting to do it face to face. If there's any way you can met her for something this summer, even if it's just at the mall, it is way better to do these things face to face. I would say do the facebook thing, tell her you want to talk. I wouldn't if I liked you, I'd be excited. You know girls have that crush forever and then summer feels like the end, they are trying to move on since they think they now won't get that guy so she'll be excited. Ask her how she is, what's going on where she is, etc. If you show interest she'll open up especially if she likes you.