The gap between the first two stories is about a year. 

When they come out of the wardrobe in LWW no time has passed. It's the summer holidays. 

A year later, they're at a small railway station on their way to their boarding schools (boys to one and girls to another). It's Lucy's first time.  This time they don't get older, as this visit is only a few weeks or days. They don't revert to their adult Narnian status.

The third visit is the start of the following summer holidays. There's no age change at all.  

The fourth book is a few months later, soon after the new school year has started. It's autumn, and interestingly enough, it's Autumn in Narnia too!  The two children don't change age.

Posted by: @kj7rrv

Does this mean that a character's age is tied to time in their home world, and their age in other worlds "resets" each time they go home?

Yeah, that's the impression I get. The main characters technically grow younger whenever they get back home in every book, but The Lion, the Witch and the Wardrobe is the only one that mentions because it's the only one in which they're gone long enough to visibly age. 

Thank you! It seems, then, that there is some kind of inherent connection between a character and the world in which they are born that remains no matter how long they are in another world? I haven't read the whole series for a long time (currently re-reading the series, now part-way through PC), but I don't remember any character (including the Pevensies, as Col Klink noted) spending a long time in another world then going back "home" except in LWW. (Jadis is from Charn, but never goes back to Charn after arriving in Narnia.)

Polly and Digory only travel for a few days back and forth by the Wood Between the Worlds. In PC, I'd reckon the children from our world stay for a few weeks (or shorter) before going home. In VDT and SC it could be a matter of months rather than weeks. But LWW is the only book where anyone stays for more than a year and then goes back home.

I think the Professor nailed it, that that world would have its own time.  When he and Polly traveled from world to world using the rings, it seems to me that time still passed in our world.  I say this because when they come back from Narnia, they're shocked to find that no time has passed at all.  Now I could be wrong on that, because we don't know one way or the other if any time passed while they were in Charn, or the Wood between the Worlds.  But it seems to me that they didn't notice the difference until they came back from Narnia, so... maybe?

But I think - though this is not the most satisfying answer - the bottom line is "Aslan is in control".  Imagine how the Pevensies' parents would have reacted if their kids were suddenly their age, or worse - had gone missing for decades.  Surely, Aslan knew that would not be good.  On the other hand, when they return to Narnia in PC, Peter and Susan get the news (that made me so sad when I read it) that they were too old.  Aslan's whole purpose for sending kids to Narnia, in addition to his plans to right wrongs and save Narnia, is "that by knowing him there for a little while, we might know him better here".  He knew when the kids needed to be kids, and when they needed to grow up.

But what strikes me as odd about the whole subject is the fact that they remember being adults.  If my admittedly simplistic answer of "because Aslan wanted it that way" were correct, why not do something like at the end of the movie "Jumanji", where the MCs decide to kiss "before I feel like too much of a kid to do it".  I suppose it kinda did work that way, because Susan eventually seems to deny having ever been there and done that.. sorry, I think my answer is that really, I don't have one. 😆

Posted by: @geekicheep

But what strikes me as odd about the whole subject is the fact that they remember being adults.  If my admittedly simplistic answer of "because Aslan wanted it that way" were correct, why not do something like at the end of the movie "Jumanji", where the MCs decide to kiss "before I feel like too much of a kid to do it".  I suppose it kinda did work that way, because Susan eventually seems to deny having ever been there and done that.. sorry, I think my answer is that really, I don't have one.

We're never told any details of the Pevensies' instant transition back to childhood and how it affects them, but as far as I can see, that was intentional on Lewis's part. I know some critics have speculated on how this must have felt for them, to suddenly go from full adulthood back to pre-adolescence, and what kind of negative and even traumatic effects this must have had. But Lewis doesn't even go there. He's writing a fantasy story for children, who obviously have never yet experienced being adults themselves, and he's not at all interested in giving them any kind of psychological drama.

Kids in real life often play games in which they imagine themselves in adult-like roles — including being kings and queens of their own realms — and then have to switch back to being ordinary kids when it's time for dinner or bed. In a way, Lewis doesn't treat the Pevensies' return from Narnia much more seriously than that, although we're given to understand that their time there was not simply a dream or a game. And yet Susan later persuades herself that it was. Perhaps there's a hint given in the part in LWW where we're told, during the Pevensies' adulthood in Narnia, that "if ever they remembered their life in this world it was only as one remembers a dream." It could be that once they return to their own world and their original ages, Narnia and their experiences there become, if not quite dream-like, somewhat less vivid than when they were there experiencing these things, and so losing their adulthood doesn't feel nearly as strange as most of us who are adults now would imagine it would feel to be suddenly shoved back into a child's body and mentality.

And as @KJ7RRV mentions in the original post, when the Pevensies go back to Narnia in Prince Caspian, a year (in our world's time) after the end of their first adventure, they remain the same age they are in our world and don't revert to being the adults they were when they last left Narnia. So yes, it seems their ages are "tied" to the world they came from and not affected by being back in Narnia — although we're told a few times that the "air" of Narnia works on them and makes them feel more like the Kings and Queens they once were and remember their old strengths and skills in using weapons and so on. But their physical ages don't change. It makes sense from the viewpoint of the kind of story Lewis is writing, anyway — since he's telling a story for kids, he keeps his main characters at a relatable age for his audience. It would be really strange if, just a couple of pages into the story, these child characters suddenly turn into grown-ups!!

Posted by: @courtenay

 

I know some critics have speculated on how this must have felt for them, to suddenly go from full adulthood back to pre-adolescence, and what kind of negative and even traumatic effects this must have had.

I like to imagine that when the Pevensies return to Earth at the end of The Lion, the Witch, and the Wardrobe, their physical and emotional states return back to their childhood ages. Their experiences in Narnia feel like memories, while they simultaneously feel like no time has passed in our world. They know their time in Narnia was real, but they're also transported back to their original headspaces before entering the wardrobe.

I know the Prince Caspian film approaches this differently, with Peter particularly struggling with returning to childhood after spending time as an adult and a great king. This was a valid and interesting approach for the film to take, but I agree with you -- that C.S. Lewis didn't intend to give the Pevensies any kind of psychological drama.

@courtenay It's so funny, when you say "for children", my mind goes immediately to very little ones - who wouldn't even understand half of what's in here.  Which... kinda?  I didn't fully understand where the story was going when I read LWW for the first time.  But I also didn't even begin to understand the Christian side of things until I re-read it as a teen.  idk, I think the fact that we're all here discussing it (and having fun doing it) tells me that it's not just a little kids book, like the Cat in the Hat, or even the Castle in the Attic.  He gave it such richness, detail and depth that even we grown-ups look at it with a sense of wonder, surprise, and the fun of exploring and adventure.  Which is why we like trying to figure out.  But of course, technically, you are correct - we don't know, and Lewis probably never thought about it.  And as a wanna-be writer myself, I can relate.  When you finish a story, having no idea how it will be received, you don't know if you'll ever do a sequel.  And that's one more awesome thing about LWW - it could stand by itself if it had to.  But then he got inspired and hammered out 6 more - and this age subject is just one of many strange little "plot-holes" we find when we look at it through today's nerdy perspective.  There are a lot of unknowns - which makes talking about them so much fun. 😀