I was 5’5” and weighed about 90 lbs when I learned to swim. At the age of 15, I was 5’6” and weighed 100-105, and was practicing with the swim team.
We kids taught ourselves.
There was a life guard.
It was just a country lake
We paid a couple bucks to get in from money we had earned, swim, watch the girls, fish and maybe get a dreamsickle.
We’d ride our bikes 4 mi out there along a heavy truck route with no adult supervision.
Ahh to be a kid again.