On the basis of the information you have given me, I would look into the possibility of putting him into a private kindergarten. It sounds as though he is a very bright child, not likely to be stressed by being in a class with slightly older children. Certainly he has already learned many of the things children are expected to learn in kindergarten. But be sure to talk to personnel in the local public school you expect him to attend next year. Sometimes they do not accept attendance credit from a private school, and it is conceivable that they would put him back into kindergarten once he starts there. As advanced as he is, you don't want that to happen. Also, some schools have an early admission policy for children with end-of-year birthdays if tuition is paid, and you might look into that. Usually some testing is required before a decision can be made and the child enrolled.
In thinking about what to do, you might also consider his size in relation to other boys. Size means a lot as boys jockey for social position later on, and small boys are at a disadvantage. Starting a year early may make him smaller than his peers throughout elementary school. Whatever you decide, it is important for you to continue providing stimulation and enrichment for him. Make certain you don't push too hard; that will turn him off quicker than anything. Read to him, take him regularly to the library and see to it that he has toys that challenge him to develop while giving him plenty of fun in the process.
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