Apparently you've found a loophole....
And, Justin shame on you, there are plenty of kids who have the potential, look at King Rising levitation, not the best, but it was put out by a 15 year old, look where it is today! LOOK!!!
Look, can't you see why Justin emphasized on 11-21?
That's because many people (not all of them) from this age group tend to be too eager for quick success. WHY? Because many teenagers (again, NOT ALL) have not been out in the real world (magic and the society) and experienced life as independent people.
It is only in recognizing your naive nature and understanding what "lack of experience" means that you can go about fixing the problem. You can't start to become "experienced" until you understand your naivety.
Just be honest, when you were a teenager (or maybe you are right now), you must have thought that you are the smartest person in the world, that you know everything and that all the adults around you are simply idiots. That is what SOME teenagers (I really have to emphasize that I'm not talking about all teenagers are like that, but yet, many are) feel when they get into magics.
Thus, the sooner you realize how "ignorant" you are, the more successful you can be.
So why Justin Miller chose 11-21? That's because, this "period of self-praise" generally starts with puberty. I guess you'll be agree with me that this module will grows to some maximum and thus collapses at the age, say, generally at age of 22-23.
So everyone in the age of 22 and above can release a dvd and lecture notes then?
You are absolutely wrong. Those people have LESS (I didn't say "they DON'T self-praise") tendency to self-praise, BUT they may be inexperienced.
So what's the point of emphasizing on 11-21, if 22 and above can also be as inexperienced as those of 11-21?
You are absolutely right on that. BUT 22-above tend to realize how naive they are; Thus, they won't just release anything that are "not too good".
This self-praise problem affects all teenagers. As soon as you realize, for whatever reason, that you don’t have all of the answers but the adults standing all around you actually do, you begin to become an adult. The sooner that transformation occurs, the better. The same can be applied to the magic community.
Before you drag out all the exceptions (i.e. Buck twins, Mozart, you name it), step back a little bit, and think: " Are all those young magicians that you are argueing for really one of the exceptions?"
Yes, they are the future of magic community; but maybe....not right now, when they are still LACK OF EXPERIENCE!