Board Thread:Naruto Discussions/@comment-1758775-20151007125942/@comment-2125188-20151007163357

@AsianReaper I think there is a set age cause everyone in the rookie 9 were all in the same graduating class and all the same age. I would assume it's like how normal schools operate where most kids would enroll at 5, but some enroll a year earlier or later. Kakashi was probably able to skip year levels.