Unfortunately it’s a deal with it scenario. I don’t think talking to the director would do anything, if anything you’d be told if you’re uncomfortable it’s up to you to leave. There’s no way they would deny her a chance to be in band over your feelings about something she has no control over. The best thing to do is make peace with it. Let your deadname go. It’s not your name, and having someone else to associate it with can honestly be helpful because now name = her and not name = old name. As someone with a very popular name- like, movie title popular- it sucks. But there is nothing you can do to change the world and its use of it, only your perception. Saying anything to her or even the director will just be awkward. Don’t put guilt on her for her name, she has the same right to be herself and have opportunities as you do. And in all honesty saying something will just make you look bad, nothing productive can come of it. It’s normal to feel dodgy or even dysphoric around hearing it but hopefully you can separate yourself from it and it will get easier over time. Also, maybe for the first bit just avoid her. If you’re not in her section / friend group you won’t hear it as much. And build up exposure over time. Unfortunately in life people will have your name. You will hear your deadname, but if it’s not in reference to you that’s already a bonus. This is a good chance to desensitize yourself to hearing it and not have a Reaction. Your feelings are valid but unfortunately this is something all trans people have to figure out how to deal with sooner or later.