What Should I Do When I Go Back to the Past?

What should I do if I go back to the past? My name is Ma Chao, a student from the No. 1 Middle School in Changle City, Shanhe Province, Daxia Kingdom. I have just been promoted to the second grade of junior high school this year. At the age of fourteen, he is 1.47 Meters tall and weighs 120 pounds. He is fat and short and has little strength, at least before the summer vacation. Cheng District No. 1 Middle School is the best junior high school in Changle City, but there are also good and bad classes. The class I am in is Class 200, the worst one in the grade. And I am a transfer student who transferred from the worst junior high school. I was bullied every day. Most of my cowardly character was developed here. It's such a miserable start... This novel and its characters are purely fictitious. Any similarity is purely coincidental and should not be imitated.