but here is the thing: i am very afraid that if i ask her out, and she says no, we won't be that good of friends anymore.
Even with our vast age difference, I'm in the same predicament.
Normally I'd tell you to stop worrying about chicks because you're too young, but I'm go to answer this one because it's a tough decision, so everyone take note:
Don't forget around and do what I've been doing. Let her know you dig her, and if she responds well, ask her out. Don't wait if you really like a lady, because you'll get forgeted when she finds a different guy.