Think is the same in Holland too……isn’t the best outcome then for them to be playing both? The ‘assist’ the adults in club teams, and then to ‘lead’ their peers in school?
Personally, I think 13 is far too early as boys are physically not ready to compete at a level aedequate to their skills; they usually end up in lower teams against opponents which are not as skillfull as them, so the learning effect might be limited