Should I tell this beautiful girl how I feel about her online cuz I never have the chance to talk to her alone?

So I like this beautiful girl that is 1 year younger than me (im grade 11 and she is grade 10) and I see her at school often. She makes school worth going to for me most of the time. Everything about her is great, her beautiful smiles and gorgeous eyes. I am also one of the shiest people I know... Today I saw her at lunch and I wanted to talk to her but she was like 4 of her friends and I felt so nervous that I ended up backing out like a pansy... I never really see her without her friends around. My friend told me to add her on facebook but I dont want her to feel like I just searched her up to add her. I was wondering if I should send her a friend request and include a message telling her what I feel about her. Would that be weird? And if I do see her alone, what can I do to get talking with her?