Not sure what happened to your post- but when I saw boy and July, a flag went up and I may know where you are going. When in July is his birthday? I teach 3rd grade and I have kids with July, Aug, Sept b-days, obviously

. We start school Aug 9. My boys who started "late" so, 6 or almost 6 tend to be leaders in the class, academically and socially, and have few behavior problems. They just "get it." The boys who start "early" so 4 or just turned 5 seem to struggle more. They tend to have more behavior problems, often are littler so they get teased and left out for that and are just more immature. Even when they are "okay" academically, there are still social issues. This does not seem to affect the girls quite as much, but those Sept girls- it usually does.
Now, I will say this is a generalization and July kiddos aren't as effected as the Aug/ Sept ones. I do have a boy this year with a July 12 b-day who started at barely 5, who is totally great. But, he is the only one I have had. I can say some are better than others. Last year I had 6 Aug/ Sept boys, 3 early, 3 late. The differences were huge!!
My SIL teaches Jr High and she says the young ones have a hard time or a while because they haven't hit puberty and are way shorter than the girls and older boys. She has to teach sex ed to 7th graders and says the 11 year olds are usually way too young and immature to handle it.