Actually, while we’re on the topic, according to The Journal of the Royal Sisters, Celestia and Luna learned “The Royal Canterlot Voice” from other alicorns. This happens before the founding of Equestria, and it seems to imply that Celestia and Luna grew up in Canterlot.
In Castle Mane-ia, Twilight says that The Castle of The Pony Sisters is “thousands” (plural) of years old.
I think after awhile, you sort of repress just how inconsistent the lore was.