This seems like a reasonable system, regardless of age. I age that kids should not be black belts. To become a black belt, it takes time, commitment, and maturity.
I can see the difference in myself from now to when I first started Jiu Jitsu. My game, timing, and the amount usage of strength and speed has change. I don't muscle everything I do and I make a lot of predictions on the fly. I have strategies for most scenarios and I'm able to impose my will, if I need to on some people.
Besides time, they should put other requirements on the charts to make the separations between the belt colors. Like what type of moves each belt should know or what kind of abilities that each person should have. I believe everyone should understand this system and criteria, so they can set goals for themselves to improve upon themselves to get to the next belt rank. Otherwise, the progression is slow to get to the next belt rank and getting to the next belt rank would be based most on time and consistency in
Ronnie Castro is a Big Filipino Strongman, Powerlifter, Muay Thai, BJJ, and MMA practitioner, computer geek that reads manga and watches anime while saving the world, bringing back sexy, and eating like a madman at a buffet, one day at a time..