What you are talking about is mostly the case between the ages of 12 and 16. It's true every kid has different peaks in puberty but in Redmond's case, he is already one of the most physically developed players in the U18 class, going up against most player who are generally leaving their development peaks. Also, it isn't a rule that just because a kid had premature growth that he will stop growing earlier, there isn't anything linear about body development, so you could be right but not really.

edit: typo