Hi.
Nothing's wrong with you at all. Each person comes to sexual desire in their own time and in their own ways.
Many find that their curiosity about desire for sexual contact increases starting in their adolescent years, when the body begins to react to a complex interplay of hormones. Even so, there is no one "right" timeline for these things.
You will probably develop an interest over time--no need to put any pressure on yourself to feel something you don't right now.
You seem very self aware and that's a good thing. Try to remain honest with yourself about what you're ready for and what you're not. And enjoy your crushes! When you are ready to explore the next step, you'll know it.
If you would like to talk about this with some other gURLs, head to the message boards.
Take care.