Ralph, back in the early 70's, our family used to have a membership in a private outdoor pool. One little girl was there several times a week, just like we were. She was probably about eleven years old and never wore a top and only the briefest of bottoms. I was about the same age and it never occured to that this was anything wrong or unusual. We were just a bunch of kids having fun in the pool. Years later, it struck me that in some ways our society has gotten more prudish about this.
A friend of mine has a son who was on a swim team. When the lad was about twelve or so, he and his entire swim team used to compete in baggy boxers that went below the knees. I asked my friend's wife about this, saying, "how can they win any matches dressed in those trunks?" She said that the boys were just too embarassed to wear competition speedo type bathing suits. In the 1960's and to a lesser extent in the early 1970's I generally wore a brief form-fitting bathing suit until it became so badly out of fashion that I stopped. These suits didn't hide our male contours, but no one ever made a fuss. I sure hope that the pedulum of fashion swings away from this extreme prudishness.