And we started DS at 4 in a GT program because he was acting out at 3.5 - he told us school was not fun anymore and he could not talk to his classmates. We accelerated him into pre-k at 3.7, and he became best friends with a group of kindergarten kids (pre-k and K mixed a lot especially during summer) but we knew when they left since they were already over 5, he would be miserable again even if we moved him into the new K class (which he did one week of, and hated it since it was basically his pre-k room moved up).
but every child is different. My mother was 2 years accelerated as a child, and felt that age difference through high school even though academics were no issue, and my younger sister was the youngest in her class and it was similar for her - some social struggles in early years (my parents sent her to private school during middle school years because she needed a change of social scene). But she went back to our town high school, which was really large, and in high school, she excelled and she enjoyed college.
