A few pretty good examples of the contrary are John Naber, Rowdy Gaines and Gary Hall Jr. All started competing in swimming at age 14. Gary ( I had first hand knowledge) had a short stint of swimming at age 8 for about a year, retired and began his swimming career again at age 14 in High School. Freshman year 1:04 hundred yard backstroke (hit his head on the bottom after the start). Sophomore 5:01 500 yard freestyle (hated distance swimming). Junior 46.8 100 yard freestyle…hey he can sprint. Senior 43.8 100 yard freestyle.
Genes definitely play a role, as does the work ethic…but there have been plenty of phenomenal ten year old swimmers that never came close to making the Olympic games.
There are two things to consider here (well, many more, but I’ll make it simple)
Technique, ability, feel for the water, etc : your odds are much higher if you start young. BUT there are exceptions. And if your kids interact a lot with the water when young but are not on a heavy training schedule yet, it’s OK.
Building your aerobic engine. It normally takes at least 10 years to reach the level required to race as an elite. So for someone who starts as a 10 year old, they will still be young enough to pick up more easily the technique, feel for the water part, but they probably won’t reach their top level before they are at least 20yo.
