It's all right, Sophia, don't think we'll drop you here!

It's not like we can choose who we love/care about? You really like this girl and would like her to like you! There's nothing at all wrong with that. However, the other person gets to be part of the getting to know each other situation too and, for whatever reason (which has nothing to do with you, is all her) she has maybe decided to not have such a deep relationship. It's too bad of her not to discuss it with you though, but that can be hard to do and a lot of people feel bad, just because the friendship vibes don't feel right to them. She could be feeling intimidated by you for all we know! You could be the stong person and she more afraid she can't be who she would like to be. Or, you could remind her of herself at your age and maybe that scares her as she might have had a hard time then and is afraid it will "come back".

I'd keep in casual touch with her and look around and see who else you can find on Second Life; it's a big place! Do you have a job and apartment, etc. there yet? Work on that maybe? But if you stay "constant" and just friendly, maybe she'll be more engaging over time as she sees you're just a "regular" nice person :-)