What do you advise if i smell of bo! i feel embarrassed while at school! please help!?

This is serious: I take it that you're a young person. You can ask your same-sex parent, "I think it's time I start using deodorant". If that is not practical, ask a same-sex teacher for guidance -- they understand. You can alienate friends at any age, and as an adult body odor can get you fired from your job -- they won't tell you the real reason. You MUST manage this.