To me, it's implied that Tumnus has experienced these things himself — we get the impression he's telling these tales with relish and regretting the fact that those days are gone, though it's not stated openly. I certainly always read it that way and was surprised when the BBC Radio adaptation of LWW (not to be confused with the BBC TV version) stated straight out that Tumnus told Lucy stories of how Narnia was in his father's time.

It's also true that Lewis doesn't specify anywhere in LWW how long the winter lasted — the "hundred years" does come from Prince Caspian. But given that Tumnus is a fantasy creature living in a magical world, I've never had a problem with the implication that he would need to be over a century old in LWW if he was around before the Witch's time, and yet he only becomes "middle-aged" by the end of the Pevensies' reign. As @col-klink said, there are other Narnian creatures that have much longer lifespans than humans (as we learn from Roonwit in LB), so it's not too big a stretch to imagine that this applies to Fauns as well. If, for instance, we assume Fauns live about 300 years on average, then if Tumnus was about 35 at the beginning of the Long Winter — young for a Faun but old enough to be able to remember things from before that time — that makes him 135 when he first meets Lucy, and then 15 years later, at the time when the Pevensies leave Narnia, he's halfway through that (proposed) average lifespan, hence middle-aged. That makes sense (in a fantasy world, at least) and doesn't conflict with anything else I can think of that we know about Narnia and Fauns.

As for how old the actor playing Tumnus in a future screen adaptation should be, I don't much care either way so long as he does a good job! {ym}:wink: But one thing I will mention (and I know I've said it before) that every live-action version so far has missed: Tumnus, canonically, has "rather reddish" skin. If they want to be accurate to the book AND satisfy the modern push for "diversity in casting", this is the perfect opportunity!!

Anyway, of the various young actors who've been mentioned in rumours and chatter in the news page recently, Joe Locke feels like he could offer a fresh take on Tumnus. I've enjoyed bis performance so far in "Agatha All Along" and I feel like he could bring some of that softer friendly charm to Tumnus.

He wouldn't be my number 1 choice compared to previous suggestions, but he could potentially would be a good way to instantly differentiate the show from the Walden films.

I'm not sure if The Lion, the Witch and the Wardrobe actually describes the White Witch's winter as lasting a hundred years. I believe that idea was introduced by Prince Caspian. Of course, PC was written shortly after LWW so maybe Lewis had it that way in his head the whole time.

I realize this whole post has been me talking about the books and not adaptations of them {ym}:lol: so, for the record, I'd prefer a younger actor because it would evoke the iconic Pauline Baynes illustrations of Tumnus but it's not like I can't imagine enjoying an older actor's portrayal of the character. (Jeffrey Perry in the 1988 miniseries looked older than the illustrations depicted Tumnus as being and he was actually my favorite part of the cast. He had a cool voice.)

While I do love James McAvoy as Tumnus in the Walden film, I think it would be a nice change to see an older actor. 

But suggestions that Tumnus not be played by a white-skinned actor don't immediately make me think South Asian. If fauns are Greek mythological creatures, what about a Greek actor?

Or maybe it was just an eccentric outfit with a coincidentally Tumnus-esque top-half. Who knows.

He’s a shoo-in. Listen, it’s a small part, it’s a cameo role. If his ego’s okay taking that small part, he’d be perfect I’m sure.”