Do you personally know of any adult woman who has never even once in her life worn high heels? ~

That would be so hard to answer.....most women that travel on the underground trains in London  or busses tend wear flat or low heel to go to work wearing.....
Many women in our office change into higher heels once they get to the office.......its kind of a dress code that the younger women have to look stylish and frumpy shoes are frowned upon....:( 

Its  impossible to know and something I wouldn't ask a much older person....

My sweet mother never wore high heels.  More often than not she didn't have any shoes on at all (by choice).

I've never worn high heels. I wore shoes with short heels but even then I kept stumbling and my feet were all sore.