wanting, I don't know about falling in love over the net. I think relationships are different irl, for so many reasons. But I do think it's possible to care greatly for someone, and it sounds as if she cares for you.
I'm not the best person for advice re: shutting people out, because I've had a tendency to do this myself. I guess I can recommend that you try to treat others with the same open-heartedness that you would like from them ,,,?
Best of luck