I guess this is more a question of how long ago did the events of Bard: Mountain take place relative to the present. I'm just hoping it happened long enough ago that Aurelion is some big grand Dragon and not a tiny hatchling because he only just came out of the Egg 3 years ago.
Space travel makes time relative.
I personally doubt that Aurelion Sol was that egg from Bard: Mountain specifically, but I'm wondering if it was an egg belonging to Sol's home plane, perhaps the egg of one of his own kind. It might've been kept in Runeterra for safe keeping because Sol's people are few in number and have to protect their brood, so they put it in a relatively safe location in another world where potential enemies of theirs wouldn't find it.
Old enough to party?
I'm just hoping it happened long enough ago that Aurelion is some big grand Dragon and not a tiny hatchling because he only just came out of the Egg 3 years ago.
You do realize that actual animals (let alone fake ones like Aurelion Sol) grow at different rates and not all take ~15+ years to reach their full size like humans do?
