In the congregation I was grew-up in as soon as a boy was baptized he was put on the speaking schedule. I would not be surprised if this is a common practice in the brotherhood. It has several good points: it forces the boys to study, it gets them involved in the church and it prepares them to be leaders in the church. It has a practical point to it also, many congregations don't have enough teachers so we need any warm body we can get up there.
Even with the above good points the practice of all boys, by default, being put on the teaching schedule it is a bad idea, and the bible says it is a bad idea. I'm will not be saying anything that is not already known, we just choose to ignore the bible in this case. It is a bad idea because many of these young men have no ability to teach, most of them don't want to teach but feel pressured into it, and it develops an arrogant pride in some of them.
"Not many of you should presume to be teachers, my brothers, because you know that we who teach will be judged more strictly" James 3:1. This quote from James is well known and widely ignored. We put every newly baptized boy in the pulpit knowing we are placing them under stricter judgment. A second problem is that it develops conceit in some young men. One of the qualifications for an elder is that he "not be a recent convert, or he may become conceited and fall under the same judgement as the devil," 1Tim 3:6. I know being a teacher is not the same as being an elder, but we are taking teenage boys, with little knowledge of the bible, some of whom are not old enough to drive and having them teach God's word to the congregation. Our country doesn't think you are mature enough to vote until you are 18 years old!
Many of our congregations are suffering from leaders who should never have been put in the pulpit, they were given too much authority for their age and they grew up to be arrogant men. I can think of two congregations that are now lead by one man who controls everything in the church and they feel that if you question them you are questioning God. Many congregations are controlled by preachers who have more power than the bible gives elders, but they don't have to meet any qualifications to hold their position. These young preachers started out as young teachers.
I know we need teachers, but there must be a better way than putting every newly baptized boy in the pulpit. Let's teach them first and the ones who show ability, who express desire and who show the maturity to be teachers should be placed in the pulpit. This will give us a much better pool of talent to draw from than what we have now.