I need help ....... Girlfriend troubles?

OK so here the thing i'm about to become a Jr in high school and there is this girl i like shes one of my best friends little sisters shes becoming a sophomore shes cute funny always smiling and just well how do i say this ......... well she is perfect. she isn't actually my girlfriend i want her to be but i'm really nervous because i've never had a girlfriend before and i don't know if she likes me as much as i like her. school just got out a few weeks ago and (i cant believe i'm actually saying this but) i want to go back and see her again her smiling face warms up my life every time i see it. we had a dance a few months back and i'm not really a dancer let alone slow dancing but she was able to actually get me dance and when the slow dancing started I (and i emphasize the fact that this is all new to me and before meeting her I WOULD HAVE NEVER DONE THIS) well i actually asked her to dance with me. i enjoyed myself i honestly for the first time in along while had absolutely no care in the world i just wanted to stay with her and dance forever. we did have a slight hiccup though she is a little shorter than me so she kinda has to go on her toes while i leaned down a bit. Sorry for rambling it's just that she's the first girl that's made me feel this way and i need advice because i don't want to screw this up. all we usually do is chat during class or passing periods but lately and unexpectedly after i had found where she eats lunch (i was on my way to the library and she just caught me by surprise) i would join her and her friends for lunch and buy her a cookie from the vending machine we also mess with each other teasing mostly. and we hug a lot so please i need advice because well god i just went brain dead ..............well they need to invent a new word to accurately describe how beautiful and charming and funny she is and how she has mad such an impact on my life please help.