I'm going to be a junior in high school this year and have decided that it would be best to change my name at the beginning of the school year. A few people know, but I want my change to be official. My plan is to tell the teachers when they do roll call, but I'm not sure about what to do after that. Does anybody have any advice, or stories of when they came out/ changed their name in a similar situation?

May I suggest talking with the teachers either before classes or with a counselor instead of during roll call? It would be easier if not less embarrassing for them as well as you. It would also give you an idea of how well they will treat you and your request before handling it in front of your peers.