I like a girl in my class,but dont know if she likes me, I want to get close to her but how????

No experience with dating, but 14 years old and female.
I suggest talking to her. Get to know her. You probably won't get anywhere if you don't communicate with her at all. Try to become friends with her.
After speaking to her regularly, it would be easiest to just ask if she likes you (or ask one of her friends to ask her for you).
No idea if this would actually work, but if it were me, this is what I would like to have happen.