I believe most people say a kid is reclassed if they are not in the age-appropriate grade: so depending on the state you live in if you started school at 5 years old you are "on-age" if you started at 6 you are reclassed. And then some people also repeat a grade to gain an advantage, these are also reclassed. I live in PA, so anyone born before 9/1 is considered reclassed. I will say, from my experience, most top clubs have about 50% of their players that are reclassed.