This was nearly the same approach in the association I came up in. Kids had a different curriculum (and separate ranks). If a kid finished the kids' ranks and was at least 13, they could join adult classes. I think at age 16 they automatically moved to adult classes, regardless of their rank. All kids - regardless of rank - started adult classes as the equivalent of white belts (technically, they outranked all the white belts, but nobody else, but that had no bearing in the school other than where they lined up).OK I know this has been discussed but in light of no necrothread.
Kids black belts, I have to admit in my school I don't hand them out. I don't do kids classes anymore. As I laugh when they say their kids need discipline, then I do and they freak. But the other is the when will my kid get a black belt. My answer is they won't I would only grade them yellow, orange, red and green. When they are 13 they can join the adults class and move up from there.
Personally, it all depends what you put into Shodan but the knowledge and brevity of it, I don't think is for kids. Skill level is one thing. I have seen some impressive kids.
But I don't give kids dan ranks. I actually won't do it under 16.
Thoughts
I don't have a problem with kids' BB ranks - I just believe they should be a separate rank, unless somehow they can actually fulfill the full adult requirements. Meaning, if the requirements included sparring, they have to spar against adults.
I never taught kids after I left my instructor's school. I didn't have the inclination, and didn't really have the time to add separate classes for them (I taught at most 3 times a week).