I got my own back very quickly There was a kid who always picked on my brother and when I started school he tried it with me. I hit him with a chair and his father came to see mine that evening
When the kids father saw the size of me and the size of his son, he brayed his son for being soft
I was 11 and this lad was 14.
I also had a secret weapon at school which consisted of a pair of Calipers on my leg and a boot with a steel frame on the heel.
If I stood on a bullies foot and slid my caliper down his shin, they never bothered me again