Someone wants to change bedrooms with me, and I don't want to.

I don't think it should be changed Because this is his own personality problem. You should not put up with it. At a young age, with her personality, I'm afraid everyone in your dormitory can't get along well. But if you don't agree now, she may hold a grudge. In case of extreme ideas, the consequences are unimaginable. So you can talk to her. Express your attitude clearly. You can't change dormitories. Not to help her. If there are multiple beds in the dormitory, he will be allowed in, but it is impossible to have one more bed in the dormitory. Sorry, I can't help her. It is recommended to take her to a counselor or accommodation manager, and it is best to go with her in case she says in front of the teacher that you can change beds with her. Then let the teacher solve it with him.