I am [13/m] years old and I like a girl at my school who is [13/f] aswell and I think she knows I do, what should I do?

I've been thinking about her since she first started at our school. She's nice, She has a good taste in music, music that I like aswell such as Post Malone and Joji. And I find her attractive. I am 99% sure she doesn't have a boyfriend and the only people I know she hangs out with are her girl friends from school. I know this whole situation sounds silly but I have only really talked to her when we were doing a thing together in Swedish class. We were filming a thing to show to our teacher and when we were talking I found out she liked YouTubers such as FilthyFrank, Idubbbz and Rusty Cage. I added her on SnapChat after another guy in our class added both of us in a group chat, which I think can be a step in the right direction. So far I haven't had the balls to talk to her just like that or even send a message on SnapChat. I'm generally quite bad at talking to people so you can imagine how terrifying it is when talking to her, when all I can think about is how I can't say anything wrong. Seriously, I need your help. Any advice you people can give me on how to approach this situation is very much appreciated, thanks!