MoDad,
My son has a July birthday which has necessitated his always playing up, until this past summer. He played on a 13U team and a 14U team, and based on his performance played on a 15U team in fall ball when everyone moved up a year. We are relatively new to travel ball, but all the coaches I respect have told us he should play at the highest level he can succeed at. Playing 60/90 hasn't been a problem for him pitching or hitting.
Seems at 14U this spring there are some venues here that still have 54/80, and I think that it is a detriment, maybe even a risk as the more mature boys are going to hit the ball hard, and the shorter pitching distance is dangerous to the pitcher. So his 14U team is opting out of 54/80 tournaments and leagues.