Dude, find out what's her phone number and text her. Start with 'what are you doing' and stuff then be honest and tell her what are you feeling. Add some sweet words and hopefully she will like it.
I'm 14 too and I like a girl who's 15 (just like you), she's from another town and she comes here only on week-ends and in the summer break. I tried this and it kinda worked for me.
And don't be afraid to call her. But try not to do so when she's with friends because this might be kinda funny for them and kinda embarassing for you and maybe the girl, too.
Try this and let me know if it works.