I am 13 and want to ask a girl out. Advice?

So, I have this crush on this hot girl in my grade and I want to ask her out. Im not a weirdo or a freak, I am popular and the king of the school as well. I doubt that she would turn me down. I think, I THINK, that she likes me as well. She blushes when talking to me. She flirts and laughs in our conversations.She is always starring at me in class. She is trying to get close to me. I do understand why girls would like me, I consider myself very popular, Charming and handsome, have Sleek and beautiful body. This is kind of weird but, after school, I tend to be topless a great majority of time. Playing sports, meeting with friends in public parks etc. When I do see her then, she is always just starring at me and "Day dreaming". Anyway, I wanna ask her out. Have advice?