I feel your pain. My ds' birthday JUST miss the cut-off last year for K. We could have put him in a private school K, but we were worried about maturity also. Now he just started K as one the older ones...he is definitely one of the most mature and taking on a leadership role BUT he is bored out of his gourd with the work (and has already surpassed any goals for the year academically). BUT in reviewing the first grade curriculum -he has met most of the first grade goals too (his handwriting would be a problem for 2nd grade AND he would be the youngest by 2 or more years). Sigh. I have this icky feeling we may have to go private or homeschool eventually.