What to do? Please Help!!!!!!!?

Me and this girl I've known for about 2 and half years and I really like her, but the problem is what do I do? I don't want to ask her out because I'm afraid of losing the friendship. That would be a major loss. We're both in 9th grade and have 1 cl together. This is kinda crazy for a guy, but once in awhile I get heartaches just thinking that I might lose her to another guy. I've told her about 2 years ago about my feelings of her, but I don't know if she still thinks I have feelings for her. I lack confidence also. What should I do? Thank you to people who respond to this question.