Are people afraid of me?

I'm in high school and the kids who always talk garbage and wanna start fights seem to act all tough. Since I live near the school, some of them follow me(different people on different days) and start acting all tough. As I stand in the alley waiting for them they seem to act nervous as they get close to me. Ive been doing MMA for quite a while and I let the kids start something and they don't do anything. So inside of school; they act all tough. Outside of school; they somehow start being nice to me. I always alone I can take on two kids at a time depending on how big they are. As the year has passed by, these kids don't pick on me as much. Are these kids afraid of me?