My son missed the public school cut off by over 4 months but was able to start at a small private school this year instead. It's been a huge success academically and socially, but mainly because the school offers each child an individualized curriculum. Even though DS is the youngest in his class, he is still way beyond his classmates in reading and really needs the differentiation they give him. So from my perspective, unless the $12K private school is going to give your son an individualized curriculum, it won't be worth it--early enrollment alone won't solve your problems. On the other hand, if the school DOES turn out to be a good fit and worth the money, then it's going to be awfully hard to pull your son out after kindergarten and settle for public school. My husband resisted paying for private school (and we pay half of what you're looking at), but now that DS is there and thriving, DH and I both know there's no going back.