Back in March, my youngest son and I both tested and achieved our first Dan (1st Degree Black Belt) at our Taekwondo school. This was a pretty significant occasion for both of us. My daughter will be testing for her black belt in the fall.
I will note a couple things - first, my son is 9, and he's been taking classes for about 2.5 years. I understand that typically this is below the average time frame for promotion to a first Dan, however, it is not outside the minimum parameters found at Taekwondo-network.com. By comparison, I started in Martial Arts in the mid-90s, and all the time I trained combined, I'd say I probably took closer to the 3 year average, though by strict calendar counting, it took me about 18.
I've read on various websites opinions by various practitioners as to whether a minor (particularly someone below the mid-teens) can accurately reach a black belt rank. After mulling over what I've read on the matter in opposition to children attaining black belts, I think I would have to disagree with that opinion.
The general premise from what I can gather is that minors should not be able to achieve a black belt because they cannot physically hold their own against an adult. I believe this to be an unfair comparison. By this measure, then one could argue that unless you can match the talents of every black belt of your Dan in a particular style, then you should not be entitled to hold said black belt.
In one tournament I attended, one of the individuals I sparred against was in his mid-60s and had a pacemaker. At the time, I was an 8th gup, and I believe he was 5th. I was able to beat him pretty handily, as I was more physically capable than he was. By extending the argument that a minor could not hold his own against an adult, one would putatively have to hold the position that my opponent that day would not be entitled to achieve his Dan, as he was not able to keep up with an (at the time) overweight, out of shape middle aged guy, so there's no way he'd have been able to keep up with a 1st degree, fit 20 year old. I disagree with this notion.
The black belt is, as much as anything, a symbol of accomplishment - a sign that you have mastered the patterns presented and that you have an understanding of the practical application of the motions contained therein. If we were to take a peer-based approach to the examination of this, as opposed to a mass-based approach, then it would seem to me that a minor who has mastered these concepts has indeed earned their ranking. Withholding a Dan certificate, or arguing in favor of withholding, simply because of one's age seems more a matter of pride as opposed to any rational position, if one takes this approach.
Another argument I've read is that children lack the mental acuity to appreciate the value/importance of a black belt. This, again, in my opinion, is a very subjective argument. I've seen 30-40 year olds who have less mental wherewithal than my 9 year old. I've seen some 12-13 year olds who, if you were to tell me they ran their households, I'd have absolutely no problems believing you. Conversely, I know multiple 20-somethings who still don't know how to write a check properly. Age does not, simply by passing, bring wisdom or understanding. Using mental maturity as a lodestar does not provide, to me, much of an argument against promoting minors. If a child can show mastery of skills and a sense of respect for the benchmark he or she has achieved, it is my opinion that it would be petty to withhold said recognition based solely on one's prejudice as to mental maturity.
Again, these are simply my opinions. I do not profess to be "right," nor do I believe that because someone holds an opinion contrary to mine that they are "wrong." I am merely unconvinced that theirs is the correct position.