Does BBY/ABY standard exist in-universe?

Question

BBY (Before Battle of Yavin) and ABY (After Battle of Yavin) are used to point events on LucasFilm timeline officially. But, do they exist in-universe?

BBY/ABY can't exist prior to Battle of Yavin, but it can exist in ABY to denote past events and even for calendar system. Existence of such calendar system is likely in The New Republic because Battle of Yavin was a golden victory event of rebellions (and, the new republic was their alliance).

Has BBY/ABY ever mentioned in-universe in the canon (probably, in EU)?

Answer 1

The New Essential Chronology is written from an in-universe perspective and uses the "Galactic Standard Calendar", which is pretty much the same as the Gregorian calendar, but uses the BBY/ABY chronology. This is the strongest example; it's rare for stories to reference years directly.