I'm not a strong swimmer. So when I go to a pool party, I always bring my water wings and stay in the shallow end of the pool.
I learned to swim at a young age, but I definitely had to wear these prior to that. And you should be thanking your lucky stars I had to, otherwise I wouldn't be here today...and you would be sad. Moral of the story: make kids who can't swim wear these things and they'll be around to cause trouble in 20 some-odd years