Do I have a chance? I'll answer yours..?

I am falling for my best girl friend. We have been friends for about a year. I don't think she considers me as one of her best friends. But all that aside, if I ask her out I'm afraid that our friendship will never be the same no matter what the answer is. I think about her all the time but she's one of those girls that everyone likes but no one actually asks her out. Any advice/suggestions thanks, I'll answer any of yours