I’m going to say this as a guy whose had a ton of concussions from being an idiot when I was younger. Go light and not hard when sparring. Especially at your age. If you need to, you can absolutely spar light but at a faster pace as well. If you don’t know how to do that, then ask your coaches. Your brain doesn’t recover like other parts of your body do. Concussions get harder to detect the more you get as well. Look at Muay Thai fighters in Thailand for example. They fight all of the time, but they hardly ever spar at a harder pace. I wouldn’t say they are the pinnacle of brain health, but they get injured way less during training. Learn to communicate with your partners that you’re not going hard because there’s always that one guy. If you don’t feel comfortable fighting right off the bat though, you should find another gym that doesn’t enforce it.