I'm a sophomore in high school and in the marching band. There's this junior in the color guard that I would really like to go out with. But, there's a girl in the battery that I practically grew up with. We are great friends and I think she might like me. She is really shy and I can't be sure. I need some advise. Please

So ask both out and date two till you choose one?

You can't 'choose' someone like peaches in a grocery store. It has to be reciprocal. It takes two to tango, as the song goes.
There is no need to leap from friend or fellow band member to being a couple. Get to know your shy friend better, go for an ice cream or something and walk and talk. Get to know the junior better just by being friendly and asking her about herself. Gradually you will know which one you want to go on a date with.

Asking them two to choose you may be a good way.Good luck.

You can't 'choose' someone like peaches in a grocery store. It has to be reciprocal. It takes two to tango, as the song goes.
There is no need to leap from friend or fellow band member to being a couple. Get to know your shy friend better, go for an ice cream or something and walk and talk. Get to know the junior better just by being friendly and asking her about herself. Gradually you will know which one you want to go on a date with.

Thank you for your advise :)