The problem with using youth "age" as a guide to assessing velocity is that saying someone is 13 years old does not distinguish between 13-years-and-10 days and 13-years-and-350-days - basically a full year of difference there. More importantly, "age" generally means calendar age, whereas biological age is far more important and plays a greater role in velocity. A 13 year old could have a biological age of 14 or 15. Most of those "Little League World Series" pitchers throwing 70+ fit this mold. I know one pitcher who in Little League was a man among boys. He threw in the 70s as a 12 year old and was unhittable. Total stud. Or I should say "Little League Stud", because today he is in high school, is about a whole inch taller than he was in Little League, does not throw hard enough to pitch, and plays the outfield. What happened? He was a classic early developer at 12, but by high school all the other kids caught up to or passed him.