What should i do i love this girl?! PLZ help me!?

ok so i love this girl!! i want to tell her i love her but i cant i am to shy! 1 year ago we wher in the same cl and she keep puting her hair in front of me! now that we are in difrent cles we dont talk alot(not that we talk alot when we where together)! pepole tell me to just tell her but i cant . i feel like i am scared to talk to her! you think i should tell her on facebook? WHEN WE TALK WE JUST SAY H AND HOW ARE YOU!