How old are the Dragons meant to be?

I was replaying old content with a friend who is new to the game and I was explaining the lore of the Ishgard/Dragon lore, and suddenly it hit me, is it ever revealed how old the Dragons are meant to be?

Are they old enough that they would remember the ancients, are they part of the sundered or did they come into the picture later?

They wouldn't remember the ancients, Middy came with his eggs after the sundering from another world. Remember Middy's not sundered and his covenant was with Hydaelyn.

The Omega Raids touch upon it too if you haven't done them yet.

Middy arrived on Hydaelyn pretty near "the beginning of time" with the eggs of the first brood.
This was sometime after the sundering, which was about 12,000 years ago.
Middy was already old enough to be a great dragon and travel across space, so it's safe to say that he's way older than 12,000. By several thousand years at least.

The First brood hatched shortly thereafter and are likely between 10,000 and 12,000 years old. Probably leaning towards 12,000.
All other dragons are younger.