I really appreciate everyone taking the time to share their experiences. It's giving me good perspective on both sides of the coin.
Right now, we're only enrolled in one activity-- a playful group music class-- and he's at the low end of the recommended age range and the youngest in the class. The fit is ideal socially and intellectually because he's naturally outgoing, is cooperative, and stays on task well. The other children are only 6-12 months his senior, which I think is a wide enough gap for the time being.
We're 4 months into the activity and the children are now relaxed enough to let their personalities shine. I see DS trying to gently coach other children when they don't understand the activity and reaching out to others for collaboration. It's a good fit at this age because he's able to be a quiet leader in the group.
He'll be one month shy of the age cutoff for the next age range in the fall, and I plan to keep him with the same cohort because the group's chemistry is good.
ETA: I will not be asking permission, as I've seen people with the same proximity to age cut-offs turned down.
