My child was competently operating an iPad before he could talk or walk
I had one family tell me they learned about five finger swipes from their 1 year old daughter.
My 4 year old is just now learning to use a mouse, but she's been at a touchscreen for over 3 years.
She was used to iPads, but one day I gave her my Android tablet. She was upset at first because things are slightly different, but adjusted quickly. I was shocked at how fast she picked it up.