My mother taught 1st grade for 30 years. I had a late birthday, and she made sure I waited a year. Her anecdotal experience from teaching was that the late-birt

My mother taught 1st grade for 30 years. I had a late birthday, and she made sure I waited a year. Her anecdotal experience from teaching was that the late-birthday kids who came in early weren't ready for school and often did worse / behaved worse.