How can i get this shy girl to talk to me? :/?

Well. she is in my homeroom and her name is Maggie. She is also white (awesome right? :D) I didnt really know her untill she looked at me during homeroom from across the room for about 3 minutes. lol also WAAAY across from the gym at our pep rally. yeah. thats saying something :) Anyway, i started talking to her in an art cl aftershcool and she was by herself. so i asked her about her painting and that went really well. (this was in march) buut ive never been able to have a long conversation w/ her. only like 5 words. she is just...so dang SHY! (its cute, but still!) once she stood behind me the whole time when i was in the lunch line, and she didnt say anything. (but i would) i didnt notice her untill she left. "darn!" i thought. when she is with her freinds, its a whole new person, so any advice girls/guys? ;) (its almost the end of the year, and tests are comming! gotta have a conversation before school's out!)