My brother was grade skipped in Kindergarten, but was average in height. He never did excel in athletics, but that wasn't a big deal to him. He was the youngest in his class and ended up Salutatorian. Driving was not a problem, for he had a hardship driver’s license at 14. I don't remember puberty being an issue.
My mom was also grade skipped in 2nd grade in the early 1930’s. She was very tall (5’10”) as an adult, so she had the reverse issue of being taller than all the boys in her grade (and most in the grade above her).
My DD9 was grade skipped in Kindergarten with an additional acceleration in Math (+2). She is tall for her age and most people do not realize how young she is for her grade. We did run into some issues in 1st Grade where she was the only kid in her class who had not lost any teeth, but that was about it. I’m not looking forward to puberty, but do not think it will be a big issue.
FWIW, in my DD’s school, red shirting is very popular and a lot of the shorter boys are held back. The parents do it with the intent of them getting into gifted programs and then being at the top of the class. The short boys are still short in the grade level behind, so that sometimes defeats the purpose of holding them back.
