I believe if a kid starts playing travel as soon as he hits the big field he'll be fine. That would be 13U. That's three years of ball before varsity given one freshman has ever started in the history of our high school, and soph starters are rare.
I don't see where the level of competition in 9U to 12U travel made a difference to my son. He would have been just as competitive regardless of the competition. I don't see where facing a kid from 50 feet regardless of the velocity makes a difference. And following a breaking pitch from 50 feet verus 60 feet is different.
But starting with 13U travel where the pitchers in the semis and finals of tournaments were often 5"10 to 6'2" and throwing at least 80 was beneficial. By 14U he saw some mid 80's. At fifteen he played 16U and saw some upper 80's. Due to this level of competition, he never flinched at anything he's seen on high school varsity.
I agree with bball. There are a lot of insane parents of preteen travel players with serious delusions.