My 18 month old niece was the same with my brother's iPad, being able to navigate back to the home screen, find the YouTube app, go to history, watch something from the list, full screen, rewind and go back to the history once the video had finished. She has now picked up using Android on Samsung Note II pretty kid. Kids are just really intuitive and learn very quickly by watching at that age, I was truly amazed since my 60 year old parents on the other end of the spectrum have great difficulty understanding this tech.