I have to agree with Kitsune. I'm not a parent, but I was one of those kids who was incredibly bored in school, got viciously teased and shunned for knowing all the answers, and could not relate to kids my own age. Nearly all my friends were 2-4 years older than me. My grade school principal did not believe in double promotion and I was in the same Catholic school for 8 years, and thus in the same unpleasant situation with the same classmates for all that time. Learning supplements at home just seemed to widen the gulf. I too developed terrible anxiety and a strong desire not to stand out or be noticed in any way. That took a very long time to get over, and I'm still pretty sensitive to even good-natured teasing. I'm not saying that double promotion works for all kids, but when emotional maturity is happening at the same rate as the intellectual advancement, I think it could work out for the better to just move up a grade.