For timelines, I also go with with it's dependent on who's answering. For my saga, Zoroaster gets placed at around 6,250 BC, the Western and Eastern Christian churches have different dates, Judaism ranges from 50,000 to 100,000 years, for Islam the Jinn were around before humans for many generations and jinn could live up to 1,000 years each so unknowable and pagan religions it depends on the religion. (Please note this does not represent the real world religion and is just a detail I added for my fictional saga that from very cursory internet research).
I also follow Tim's approach above and, depending upon the regio, all of the answers above are true. I don't give or have a definite answer in my sagas as the characters in my sagas have their own beliefs.
While not canon, I also leave the concept of whether the Divine is actually the Supreme realm in doubt. I follow all of the game mechanics for it overwriting auras etc, but there is no involvement from the Divine except through agents while with the religions based off of faerie deities said deities will actually intervene and be seen (the 'our gods walk among us' approach as articulated by Lagertha in Vikings is a similar example).
If Prometheus, for example, were to be interrogated by magic all results would give that Prometheus created all men from clay. On a angel based on the Abrahamic religions, all results would give that humanity came from Adam and Eve. The age of the world would depend on either whom the regio sprung from or give indeterminate results (Empyrean auras).
For Zorastrianism an angel (yazata) would give results consistent with Zorastrianism.
Essentially, I make the actual age and creation unknowable so that any answer could register as perfectly true, even if contradictory. Knowing the actual age of the world and which religion is the most powerful or most correct remains completely undefined. Something like Silverpit Crater can then easily fit in without any explanation needed.
TLDR: I like multiple explanations for unknowable knowledge such as who created the world, age of the world, etc in my games. Depending on the regio and whom the characters speak to, different answers will register as true even if the answers contradict each other.