You all are talking about the disadvantages of grade skipping and being physically small, but I see little talk about the disadvantages of not grade skipping. My older sister and I were both grade skipped. But then my parents moved to a new school district and that district claimed to have an etched in stone policy against grade skipping. My sister and I had to go back to our age grades. It did not feel like repeating a grade socially or anything. But suddenly, both of us who were very academically adept were stuck in with kids who had little interest in school. For me, personally, I felt awful. I wanted to learn. I could not relate to kids in my age grade who were so far behind me academically and intellectually. We tell people not to judge someone by their looks. But then, we withhold academics from someone who just doesn't "look" the part of an older grade, even if they are indeed there. I was miserable for the next three years. Finally, around 7th grade, things started to pick up. But honestly, I grew to hate school so much by then that I do not think I ever recovered.
