Questions from 'The Hobbit'

[Huinesoron]

How old is(n't) Smaug? I've always assumed he was ancient and terrible, but:

Originally Posted by Inside Information

... most of the plunder was meant to stop there in the town by the shore that in his young days had been called Esgaroth.

Which sent me back to:

Originally Posted by An Unexpected Party

"'Five feet high the door and three may walk abreast' say the runes, but Smaug could not creep into a hole that size, not even when he was a young dragon, certainly not after devouring so many of the dwarves and men of Dale."

Is the implication here that Smaug was young at the time he desolated the Mountain? Or is Esgaroth a lot older than it looks, and Gandalf just unclear?

EDIT:

Originally Posted by Inside Information

"I laid low the warriors of old and their like is not in the world today. Then I was but young and tender. Now I am old and strong, strong, strong, Thief in the Shadows!"

Again, is Smaug really saying that a couple of hundred years takes a dragon from young to old?

hS