A little in first grade, and once that I can remember in third grade. I was in private school in first grade and lived near West Point Military Academy. So I went to school with a bunch of officers' kids. They hadn't learned their fathers' ranks didn't matter off post. By the third grade I had learned to stand up to bullies, especially when they picked on others, that when they tried to bully me I had others stand up for me.
Bullies are insecure people who try to direct negative attention away from them and put it on others. Most are sad, small minded people and they should be pitied, not feared. They feel bigger by trying to make others feel small. With that understanding I learned it had nothing to do with me, and everything to do with them. And then when you point that out to them in front of the crowd they are trying to impress they usually back down. If they threaten physical harm remind them when you press charges, an assault charge will not look good on a college or employment application.