Did common people know the date in the 17th century?
Virtually all people would have known the date. The church calendar would ensure this. Many of the coins of the time bear the date, and even more significantly, so do the small copper tokens traders produced to make up for the lack of small change. The AD year date we know today became more widely used from the 15th century on. Before then, people were more likely to say “The seventeenth year of King Edward’ etc.