I just re-read some pages of The Fellowship Of The Ring and I don't get why so many people take issue with around-20-y/o Elijah Wood being cast. While Frodo Baggins is indeed canonically about 50 years old, the book specifically mentions how he looks like someone fresh out of his teens because he kept the One Ring for multiple years, which is known to keep their owner young and fresh (at least at the beginning until they rapidly age after getting rid of it) - not to mention that since hobbits age slower than humans, Frodo would only be in maybe his 30s. On one page we are being told that multiple people gossip and wonder about how young he still looks, including Gandalf. So if anything, you could say that Elijah Wood was too skinny or too attractive (though I do think he looks like Frodo is described), but not too young.
And I actually like that he looks young because it not only does it make him look cute and innocent, but we also get the notion of someone who has had a relatively quiet and happy, sheltered life before (aside from the terrible death of his parents) and of someone who is visibly sensitive and innocent and gets taken care of a lot. The BIGGEST reason I like his young looks however, is the parallel to young soldiers who are ripped out of their homes by outer forces, by older men who are the ones who started the wars. Young soldiers whose lives are practically destroyed before they even really begin, just like Frodo's - even if he's already half a century old. He comes back traumatized and sick/disabled having saved the world but having lost so much. Most likely his innocence too.
exactly.
it's supposed to remind you of ww1 and like that.