I would definitely NOT take this angle. There is nothing wrong with being a bit shy, but sometimes you just have to bite the bullet. My advise, next time you speak with her, hopefully face to face, keep it casual. Find a local bar which is having a band which doesn't suck. Tell her about the band, let her know that you and your buddy or buddies are going to see them and suggest to her that she show up as well.
Short Example: "Me and my friend are going up to INSERT BAR NAME on Saturday night to see XYZ BAND. I've seen them before and they put on a good show. If you aren't doing anything, you should stop by and check them out, it will be fun."
If she shows up, then you know there is interest. If she doesn't, then you move on. Simple. I used to work at a bar and I used this ALLLL the time. If I met a girl I liked, I would tell her where I worked and invite them to stop by. If she walked into the bar, I was in like Flynn. If she never showed up, no harm, no foul. Keep it simple.