vk…again, all the other activities you mention are irrelevant. This isn’t about concussions. CTE isn’t a result of a few concussions. It’s from hundreds or thousands of head-jarring collisions over many years. No other sports involve so many collisions like this, not hockey, motorcross, not even boxing.
So get your facts straight or stay out of this discussion.
There is no reason to start this clock on pre-teens whose cognitive functions are still developing. They can wait, and if it drives them into other sports instead, so what.