In my area there are sports you can absolutely start at 12, or 14 or 15 and play in high school, but swimming, baseball, basketball, soccer and lacrosse aren't on that list. Even kids who have played for years get cut at the HS try outs.
On the other hand, football, track, wrestling, co-ed volleyball (but I think not women's volleyball) and cross country will take anyone who shows up to try outs.
I agree. Dd13 mentioned something about trying out for HS soccer in a couple of years - she played rec up until 2nd grade. I and told her to do track (dd11, ds11, and ds17 have been playing soccer since the age of 5). She just missed too much.
Here, almost all of the kids playing little league, and then Babe Ruth, have been playing since the age of 4. In order to make the HS team, you have to had been one of the top 2 players on you LL team. Ds17 was probably in the top 3 - always made all stars - but knew he wasn't good enough for the HS team.