It can be a real mess when trying to figure out ages and birthdates for 18th c ancestors, or 17th c for that matter, and depending on where from, 19th and 20th c. The calendar adjustment is so far out of living memory, and probably never mentioned in American history classes (which concentrate on Black History Month, Herstory, and how all Republican Presidents were evil, except for Lincoln who was really a Democrat; wedged between self-esteem class and self-criticism class), that it's nearly as confusing and upsetting to some folks as when they learn about the history of US currency. :')
I have done a lot of genealogy and I don’t remember ever reading this, no wonder I had so many problems determining whether I was talking about one person or two. Shows I’m not as good a researcher as I thought. :)