Asking a guy out

We are both freshman in high school. He is a Sagittarius, I'm a Scorpio. We met in sixth grade. I liked him from the start. He has always been so nice and funny. He I also easy to talk to so I never got nervous talking to him like I did with other guys I liked. I want to ask him to the Girl's choice dance (Sadie Hawkins or Turnabout). It's a valentines dance so you have to go with someone if you're going. I don't think he likes me but he I think he did in the past. He is too nice to reject me meanly so I'm not worried about that. I don't know if he's going with anyone though. He's part of my friend group so I could ask one of my friends but I'm kinda nervous. What should I do? How should I ask him? Should I ask one of my friends if he is single first (I'm not close with my friends that know him well). Would it make it weird between us?