Lyndy could "swim" when she was very young. I don't remember exactly how old she was (3ish?), but a lot younger than most kids.
We loved to encourage her to jump off the high dive, because we loved watching the life guards get nervous and move to the edge of their seats. She put on a good show by acting like she didn't know what she was doing every single time she did it. Every eye in the deep end would be on her tiny form as she shuffled to the end of the board, paused for effect, and fell like a deadweight off the edge.
There was visible relief when she finally came up for air, but no one was entirely comfortable until she'd made it to the side (paddling mostly underwater, just coming up for air). She occasionally got rounds of applause.
We were so proud.