Don’t be ashamed. This is the worst I used to panic so bad whenever it was my go. My trick was mumbling so if I stuttered it wasn’t too noticeable. I wish I could go back and just say hey miss/mr I don’t want to read because I stutter so :). It’s so unfair, we shouldn’t be made to do this. You could always talk to tour teacher privately and let them know what’s going on. I know that’s daunting but honestly there’s nothing to be embarrassed about. The likelihood is they’ll understand and won’t make you read, or you can only read when you feel comfortable. You can just tell tour peers reading gives you loads of anxiety or whatever, or you don’t even have to tell them anything if you don’t want to. It’s your business!