When you are four or five years old, your idea of waiting a very long time for something is about eight minutes, perhaps 12 minutes, but that would be pushing it.
Instant gratification is: NOW!
(Some adults might want to remember this, because nothing is more unattractive or unbecoming in a grown-up than this infant-like behaviour.) Like everything in life, from learning to swim to playing the bagpipes, it is best to start young. Your children are not going to be afraid if they see you acting confidently and having fun in the water and when learning the pipes you start with the chanter.