Is there any chance the special education pre-school he’s in now would let him stay another year even though he is technically aging out? They might be more understanding If you have to leave him out next year, it will be okay. My son went to a private church pre-school ages 3 and 4 and 1/2 day kindergarten there as well. Academically speaking, he could have gone on to 1st grade, but he just was too immature. He started K at 6 and we have never regretted that. He’s 15 now and doing well. Definitely follow your instincts. You know your child better than anyone.