Just a thought I had, like what can a ten year old do(besides mass murder & accidents) that messes up their life so badly that it is unrecoverable?
It has to be something that is self inflicted and not something that is the cause of others around them.
Any significant injury that results in paralysis would be a potential candidate. These become possible as soon as you become old enough to climb things like trees.
A kid in my class put his arm inside a… I don’t remember if it was a lion or tiger cage back on the 70s before safety was a thing. Being armless isn’t the end, but I bet he regretted that decision.