I'd like to know James Bond's age window. He's been played by a wide variety of actors. What is the youngest and oldest Agent 007 has been portrayed to be?
As jamesbond.wikia.com states
Because the James Bond Film Franchise has lasted nearly sixty years, the characters do not age in relation to release of the first film. Rather, Bond is always mid-aged. Likewise, in Ian Fleming's stories, James Bond is in his mid-to-late thirties.
That means he always aged from mid-to-late thirties. With an exception of Moonraker
But it's the case for the novel, I am not sure about the movie, because I didn't watch it.
If you go with the actors age, George Lazenby was the youngest Bond at 29 years when he was hired for On Her Majesty's Secret Service.
Moore is the longest-serving James Bond actor, having spent 12 years in the role (from his debut in 1973, to his retirement from the role in 1985), and having made seven official films in a row. Moore is the oldest actor to have played Bond: he was 45 in Live and Let Die (1973), and 58 when he announced his retirement on 3 December 1985.(source)
Speaking of the literary character, James Bond, Ian Fleming (creator) did not provide a date of birth, though James Bond is supposed to be in mid to late thirties.
In Moonraker, he admits to being eight years shy of mandatory retirement age from the 00 section—45—which would mean he was 37 at the time. John Pearson's fictional biography of Bond, James Bond: The Authorized Biography of 007, gives him a birth date of 11 November 1920, while a study by Bond scholar John Griswold puts the date at 11 November 1921. According to Griswold, the Fleming novels take place between around May 1951, to February 1964, by which time Bond was aged 42.
In Casino Royale, Fleming states that Bond bought his Bentley new in 1933. So if he was born in 1920 or 1921, that would mean that he was 12 or 13 years old when he bought this car? Not really likely. Presumably he must have been at least 18 (and equally presumably quite well off) which would give him a birth year of about 1915. This would fit in with Casino Royale as it is set in 1951, giving Bond an age of about 36. I don't know how this fits in with the other Bond novels as I've only read Casino Royale so far!