A Problem with a girl?

I am 16 and there is a girl in the year below me 15 of course who i like. She is very attractive (to me most of my friends don't see it). I got her number and texted her a bit early this year. But i mentioned in the texts that i wanted to say hi to her a lot but im not good at intros (TRUTH). I'm not a shy guy at all, in fact the eexact opposite, but it's just her that makes me nervous. We had sports day quite late this year, and she was sat behind us. My mate who is into drama (not gay but in a relationship) went back to talk to her and her mates. Every so often i would lean back and ask him a question, but every time i looked back she was always starring at me, even before i asked the question she starred, and when i looked at her she looked away quickly. I can't really say hi to her anymore because of what i said though (awkwardness). She seemed really into this guy in U6 which is the last year of senior school in England. They went out for like 2 weeks then split up and are still friends. But he has now left so hes out of the picture. Just in case you're wondering. I am not arrgant, almost never get angry, am fairly attractive, in good shape and considered "charming" by a few of my friends (girls). Any ideas on what I can do?