Before retiring I worked in our local library, and it would sometimes astonish me how people quite a bit younger than I was had not a clue. Sometimes they needed to apply for a job online, having never used a computer. We didn't always have time but if we did it meant sitting with them for ages, not just the application but helping them to set up an email account - and then explaining that they did not have to come back to that particular computer to use it!
I particularly remember the sheer frustration with one woman who invented a very complicated password - (so nobody will be able to guess it!) - and refused to write it down - I had told her that she must put it in EXACTLY or it wouldn't work - and lo, having spent ages setting the account up, she couldn't remember it accurately. Such a waste of time.
OTOH there was once an old chap who must have been well over 80 - came in with a newspaper cutting with a website about something he was interested in. He had never touched a computer in his life. I showed him the basics, clicking on links, going back, etc. - he got it right away and was so delighted - went off saying it was wonderful, he was off to buy a computer at once!