I held back both of my boys. My oldest is now in 4th grade and my younger son is currently in Young 5's. They tested as being ready academically, but I really felt that another year of emotional maturity. Also, down the road in junior high and high school, I really liked the idea of them being one of the older, and hopefully more mature, kids in their class instead of one of the youngest. We'll see if it works out that way, but so far I have absolutely no regrets about holding them back and would definetly do it again.