[aptimpropriety]

I was young for my year after being pushed ahead a grade. I did fine academically, socially, etc.

Two factors that make me want to start my future kids late:

-Social maturity: it's way easier to handle social dynamics with a year extra of emotional maturity. Particularly important in high school and college

-Physical maturity: older kids often perform very well in high school sports. I, for example, grew and gained ~15-20lbs after I graduated high school (playing sports). That would have made my HS sports career much different, and therefore college prospects as well

I don't see any reason to starting kids early for upper/middle class folks, besides parent's bragging rights.