(Thanks to The Hobbit Tribute Magazine by Topix Media and writer Jan Sterling.)
In the Second Age of Middle-Earth~~
2850: Gandalf finds Thrain and receives the key and map of Erebor.
2941: March 25~~ Gandalf and Thorin have a chance meeting at the Prancing Pony in Bree.
April 26~~ The Unexpected Party at Bilbo’s.
July 16~~The Company is captured by Goblins dwelling deep within the Misty Mountains.
July 17~~Bilbo is lost inside the Misty Mountain tunnels and stumbles upon the Ring.
July 19~~Bilbo encounters Gollum and narrowly escapes with his life (and the Ring) after besting the creature in a battle of wits.
A group of vicious Wargs traps the Company in the tops of some trees, but the adventurers are all saved by Giant Eagles (and this is likely where the first of the three movie ends).
So, if Thorin is 200 years old at the time the film is set, would that make him in his late 30s when the attack by Smaug took place?