If I ask a person today what year they believe it is, 99% of people across the globe will correctly tell me 2022.
If I went back to the year 1700, I imagine most people, though probably not quite 99%, would know it was 1700. If I went back to 1400, would the average person know? 1200? 800 AD?
Only yesterday, there was a very similar question which u/WelfOnTheShelf, myself, and u/Nice-Ad-4281 answered by linking to some earlier threads. It is important to remember that there have always been other calendars, both now and earlier in history, than AD: for this I can recommend this by u/Bread_Punk and (in a slightly humorous fashion) this by u/DanKensington and u/TywinDeVillena