How do I get rid of this childish crush?

I met a girl on a gaming site, got to know a lot about each other. I took a liking to her and started private messaging. This was all before I had even seen what she looks like. Well after months and 50 private messages, I gave her my FB and she friended me. I was very impressed when I saw her pics, she has a warm, girl next door look. She had already seen my pics long before as I gave her a link to my dating profile long before. Unfortunately we live in different states, very far apart, so meeting her in person probably won't happen. Even if it did, I don't think long distance is much of anything.

I'm seeing someone locally and the whole time I'm with the girl I'm seeing, I can't get someone I'll probably never meet, out of my head, I feel like when I was 14 using chat room. I've never talked to her on the phone, I haven't even wrote to her in months. The reason being, if we talk and get closer, that will make it worse.