We have covered this topic in the past, but an SF K Files visitor suggested that we cover it again for those parents going through the process this year. Seems like a great idea.
"To redshirt or not? For all of those who have fall birthday kids, boys and girls. I've heard every rationale under the sun, Pros: that the older kids thrive through high school, do better in sports, are more coordinated, that it doesn't matter as much in lower elementary but in middle and high school socially it makes a big difference to be the older/most mature. Cons: that your kid who may be K-ready at almost 5, maybe bored out of their mind not only in K but through elementary school, or even worse, be turned off by school altogether by their K-1 experience.
For parents who have made this choice in the past, what was their experience and would they do it again?"
Here's a link to a post where this topic was covered in the past: