I had the opposite experience. My attention and productivity during my boxing years was way greater than now. Could have been the discipline I got from training

I had the opposite experience. My attention and productivity during my boxing years was way greater than now. Could have been the discipline I got from training leaking to other parts of my life. Who knows, but I know I did way better with most aspects of my life when training than not training. But related to your story, your coach was an asshole. He should have refused to let you fight. There is a reason at the lower rankings (pro and amateur) people are matched by similar number of fights. Here in Portugal, you even have 2 leagues. Rookie and Veterans, where your first fights are in the rookie league with people with less than 3-4 fights. Usually coaches try to have only 1-2 fight difference. When you have a certain number of fights (I think 5 but not sure as it was a long ago) you graduate, but even then, you don't really seem more than 3-4 fights difference. Sure, you may have someone that has been training for 6 years and only then taking it's first fight, but that is rare and usually, the idea is to rank similar fighters to avoid having a bloodbath as it happened to you. Again, and specially because this was a school environment, the coach should be fired and prevented from coaching ever again.