The Thirteenth's time line flow (POSSIBLE SPOILERS)

[Iscah]

There is a period of time between Sundering and First Calamity that we know nothing about on the Source. "The Age of Gods", originally used to refer to anything prior the First Calamity, should now apply to this era of no known records, where the recently sundered had to get used to their new forms and vague memories.

The "Age of Gods" seems to be intended to be the ancient world before the Sundering.