A Classmate Has Recently Become Very Conflicted

Hello, I am in charge of my class. At school, a classmate has recently become very conflicted - she insults everyone, she gets annoyed with whoever falls out of class for no reason, and with this behavior she provokes them to get up and make fun of her. As the person in charge, I felt it was my duty to stop her in some way. I went and asked the school teacher to talk to her, change her attitude, and so on. How do you think I did well