Two weeks ago while visiting my parents I gave my youngest niece who’s 11 years old a Feadóg whistle. My niece has spent the last two weekends with my parents and has been trying to learn the whistle on her own only for a couple of days in total. Yesterday I tweaked the whistle as it was a bit shrill and showed her how it’s supposed to be played by playing “Haste to the Wedding”.
An hour later she came and asked “Can you show me how to play that tune?”. I sat down with her about twenty minutes and showed her how to play the tune very slowly and much to my surprise she picked it up! I also showed her how to make cuts taps and crans and told her that the ornamentation is stuff that you can add on later. Yet an hour later I heard her practicing crans the way I told her that I used to practice them (By walking up and down the scale making crans).
It surprised me how quickly kids can learn to play the whistle. 
If she will follow in her uncle’s footsteps and continue to play without loosing her interest she will be a great whistle player and long before that she’ll be a lot better than me.
So, what can be learned from this little story? -Stick a whistle in the hands of a kid and they’ll learn to play the whistle a LOT faster than you did (unless you learned playing it as a kid). 
Cheers,
Anders
