About the same as whether cheesecake is a cake … or not.
Seventh century BC if we want to be more accurate.
Nope, you'll upset people using different calendars. BCE, Before Common Era.
Hope you didn't call today "Thursday", you'll upset people who don't worship Thor.
BC: Backwards Chronology
AD: Advancing Dates
What makes this era common?
How is "BC" more accurate than "BCE"?
The 'C' in BC reflects what event makes the era 'common', 'common era' is meaningless on its own. Whether or not you're religious, the birth of Christ is a convenient starting point for the western ('Gregorian' - who is Gregory?) calendar.