Our limit is 14 which is low enough but some have been graded younger which I think is a shame as I too
mostly agree with Ksan. The issue though is not too lose the all important teenagers, so how do you keep them interested if they have followed a path of grading every xxx months then you say oh sorry you have to stop here for 2-3-4 years.
My son is going for his 1st Kyu at Christmas so next Christmas he'll be going for his BB, he'll only be 15, he's not missed a class except for family holidays in 4 years, he trains every bit as hard, has just as much commitment and focus and... (I could go on
) as the average 18 year old I even think he has the maturity to wait for 3 years but I also don't really want him doing knockdown too young so what would he be training for 3 years? Like other teenagers he has a lot of distractions and as he gets older this will only get worst so I really wouldn't want him to loose interest in his training at this age.