I agree with others that this depends on the kid. FWIW, I was always the youngest in my grade, and I finished all my high school classes at age 16 and started at our local university at age just-turned 17. Granted, I was still technically a high school student, but I was in college full-time through PSEO. One of the highlights was a spring trip with the University French Club to Paris, a high school graduation present from my parents. The drinking age was lower there... I never had any issues with being younger. Most of my friends throughout high school were older than me and in higher grades anyway.
