Someone asked me the other day about when I began learning the piano. It's so long since I began - something like 63 years - that I have no memory of learning how to move around the keyboard, or of learning to read the notes. Somewhere along the line I found I was able to sightread more readily than some musicians, and that led me into a career (professional for a short time, but mostly amateur) as an accompanist and repetiteur. Not everyone goes this way: there are just as many, if not more, musicians who learn to play more by ear than by reading. It has its advantages and disadvantages: once you've got the notes under your belt you can sit down and play most popular music with relative ease, but it also means that you never quite learn to read as comfortably as you might.
I don't envy anyone beginning piano. Though children are more natural at learning than many adults, learning the piano is still a major undertaking. Instrumentalists who play only a single note at a time, look on with wonder at pianists (or organists, or anyone who plays a keyboard instrument) because there are so many notes going on all the time. Pianists probably often wish they had only one note to play at a time: by comparison with what they have to do, this would be a piece of cake!