After reading this, I just looked up the Little League World series and the age is 11-13. You could turn 13 after May 1st but not Aug 1st. And most of the players were 13. Now you cannot say that these players just happened to have their birthdays so they would be the oldest and happened to be the best players. In a large sampling size, maybe the few months difference does make a big difference in the development of coordination, giving them incentive to practice more.

But if you red shirt,maybe the kid loses the practice time and has delays in ability. Would you keep them out of little league and stuff if you were redshirting?