Maybe let him start pre-k and then you can have the teachers opinion as well to see about K. Lots of kids repeat pre-K. My dd went into school early as she had an August birthday and the cutoff was Sept. 1. My second son started late, as we moved from a private school where they moved up from the pre-K program based on testing to a public school in another state with a strict cutoff. He has already started K, and was already reading and doing adding and subtracting, so I saw no point in putting him back in K, so I kept him home. That was actually a great year for us. He wanted to learn to cook and garden, so we did that and had a great time together. He is now in 8th grade and doing fine. DD is now in fourth grade and I am homeschooling her cause she got behind. But socially she is doing fine.