Here, where I live, the cutoff for school is September 1 and school starts mid August so you could start school before you turn the age for school which is crazy. I have an August baby and a May baby. The August Baby I chose to hold back and wait to start school the following year. She would have been 4 turning 5 when school started and because others choose to hold their summer birthdays back here, some kids would have been 6 starting the year when my kid was 4- that is a HUGE difference in maturity, height, etc. So now, she is not even the oldest but somewhere in the middle but certainly not the youngest child. She has had no issues, handles things that come at her well and is a confident kid.
Now my May baby- she is really smarter book-wise than her older sibling- she has a higher IQ. She is one of the youngest in her class because we chose to send her to school knowing that she was smart enough to handle school. I see a big difference in the homework that comes home, her handwriting, and to us, she is not as mature and you can just tell that there is a year difference and she will be one of the last kids to drive which scares me because I'd rather her be the one driving than have her in the passenger seat of some other new driver. It is scary thinking about that.
Also, sports. We do swim team. The cutoff for that is June 1, so for each age division, whatever age you are by June 1, that's the group you swim in. For our elder child, this works out fine- she is one of the older kids swimming in each age bracket each year- it gives her a slight advantage. Our May birthday is on the short end of the stick because she is swimming against kids that when she just turns 7 this May, she will have to swim against a child that might turn 9 in the Fall months and you can only imagine that kind of difference in maturity/athletics at this age.
There is a book written here about that very subject- athletics and kids' ages and how it affects them throughout their lives. Our May birthday just cannot compete with the older kids. She is not built that way. So, we have found other things that she can excel at and feel good about herself doing. It's not fun to finish last all the time!
I don't worry at all about intelligence and birth month. I think that is just part of your DNA.
