||Age in LOTR
||2 Boromir and 3 Théodred
||2 Faramir and 4 Sam
||Gandalf the White
Ages of the characters in
The Lord of the Rings
The Third Age began when the Ring was cut from Sauron's hand. So the dates I'm giving are the number of years since the beginning of the Third Age. The Fellowship set out from Rivendell on Dec. 25 of T.A. 3018, and everything after that takes place in 3019, so I am giving the "current ages" of the characters at the end of LOTR.
1 Tolkien never gives a birthdate or age for Legolas. The movie invented one for him, but their figure, 2931, is actually Aragorn's birthdate! See my article or Michael Martinez's "Speaking of Legolas", listed in its bibliography, for the reasoning behind the age given above.
2 People with Númenorian blood age more slowly: that's Faramir, Aragorn, and Boromir. Denethor spent too much time meddling with something he shouldn't and was prematurely aged.
3 The movie seems to have made Théoden and his son about 20 years younger than in the books.
4 A rare slip from Tolkien: the birth-date given for Sam in his family tree is 2980, but in the Tale of Years it's 2983. So he might be three years older than Faramir.
We don't know when many of the Elves were born. High-elves lived in Valinor before the First Age began, so Galadriel and Glorfindel are well over 7,000 years old. Sindar, including Celeborn and Legolas' father, lived in Doriath before it fell, so they have to be older than 6500 years. Elrond, born near the end of the First Age, is about 6500 years old.
Re: Gandalf — Yes, yes, I'm pulling your leg. Gandalf the Sparkly White is new, but he's been around in some form or other since the world began.