text-based relationship : feeling weird about it

So basically I've met this girl in an online game a month ago, and for some reason I started writing to her on skype about basically anything I could find. I don't really know why I even started writing to her so much, whether it was just because it was a girl online (as ridiculous as it may sound) or because I really felt like I did like her. In any case, from then days passed when we wrote more to each other in a day than I wrote to my friends in a year - basically my whole day was writing to her, sometimes playing a game or two with her, and then writing to her again.

We've come to a point now where we consider each other boyfriend/girlfriend which are grand words to use knowing all we really do is write to each other. I have heard her voice, and she has heard mine, but that was mostly in big skype conversations and we never really talked 1on1 because we both agree that would be extremely awkward (and we both are shy and awkward) and we have shared photos, but the rest is all just text. I did tell her I'd visit her as soon as possible (from Europe to Australia) though...

The thing is, I don't really know how to feel about all this. I don't know if I love her, or if I'm just trying to force me into loving her or if I just like her a lot, or nothing. When I think about it our relationship being merely text-based I can't really know, can I? In the evening I somehow am always happy that the last thing I do before going to sleep is have a 2-3 hours writing section with her, but in the morning I always have this feeling that I don't really know what to think about all that, and then I'm scared I don't love her enough or something like that and it's a horrible feeling because for some reason I WANT to love her.
Has anyone had a similar situation ? Can this relationship even work out if I'm so doubtful about it ? Am I just being childish and asked her out just because I could ? I feel kind of lost and I don't like the fact that my feelings about this relationship vary the whole time... anything to say about it ?
Thanks in advance : )

PS: I guess it may be useful to know I'm 19 and she is 17, if that is of any importance.