We were clueless that our son would play in college when he entered kindergarten.He has a Sept birthday, but we felt he was ready. He was also always a well adjusted student who did well in school most years. By the time he got to be a sophomore in college we realized many of the freshman were older than he was. Many of them started school late with sports in mind. We were told several times over the years we should hold him back. I never saw a good reason to hold him back. He had good grades and lots of friends.
My son is now a senior in college and still playing baseball, two others in his class are still playing baseball. One young man from the class behind his is still playing and has not seen much playing time. Talent will win out. If one works hard and has the talent he will play.