I would like to know what "A millions years ago" means in the following sentences:
‘So Charlie boy,’ Johnno says, ‘tell us. How did you two first meet?’
I think at first he means Charlie and I. Then I realise he’s looking between Charlie and Jules. Right.
‘A millions years ago . . .’ Jules says. She and Charlie raise their eyebrows at each other in perfect unison.
‘I taught her to sail,’ Charlie says. ‘I lived in Cornwall. It was my summer job.’
- Lucy Foley, The Guest List, Chapter 12
This is a thriller novel published in 2020 in the United Kingdom. One hundred and fifty guests would be gathering at some remote and deserted fictional islet called Inis an Amplóra off the coast of the island of Ireland to celebrate the wedding between Jules (a self-made woman running an online magazine called The Download) and Will (a celebrity appearing in a TV show program called Survive the Night). The day before the actual wedding day, Hannah, the wife of Charlie (Jules' friend), arrived at the island and is now at the dinner party for the rehearsal dinner with only some selected guests. And during the party, Johnno, Will's friend, asks Charlie and Jules as to how they came to meet each other in the first place. At first, Hannah thinks the question is directed to Charlie and herself, but soon realizes that it is for Jules and Charlie.
In this part, I wonder what "A millions years ago" means.
Is Jules saying basically like "once upon a time", with some wistfulness...? Or perhaps, is she saying "It would take a million years to tell you how we met, because it is a long story"?
And I wonder why it is "a millions years ago" rather than "a million years ago". I am wondering whether it is grammatically okay ('a' + plural), and guessing there might be an idiomatic expression regarding it, though I cannot find it...