Can i still tell her what i feel? Please keep answering i need more opinions?

[dst]

Well, at first i'm 16 and she's 18, when we were on school i dind't talk To her that much i just say "hi" many times, but next year she's going to university and i'll still be on highschool but the thing is that i like her but i dind't tell her on person a friend told her and she was surprised about what my friend told her but said that i had no guts to tell her in person but that's all she said, but i don't know why or if it's just my mind that wants me to feel better but i have a strong feeling that she likes me 'cause she always looked at me and smile a lot and when i said hi she looked at me very happy not as she looked other people but i really want to tell her my feelings about her but i don't know how to sorry this was long but i really need help 'cause i feel a little depressed, i don't know if i can talk to her over facebook and ask her out or i don't know i really need an advice 'cause i think i made a big mistake ( but remember i wasn't a friend of her we just looked at each other many times and say hi but that is all ) i don't know if better don't say anything... Please help and i really appreciate this... Thanks