Where do we find that Caspian was the same age as Peter???????? When (in the book) the subject of a duel with Miraz comes up, the point is stressed that Caspian would not be taken seriously challenging Miraz BECAUSE CASPIAN IS A BOY. If Peter is no older than Caspian (his former Narnian adulthood, eventually reversed, does not count here), how can AGE be invoked as an argument for why Peter would be taken any more seriously???
Actually in Chapter 13 of
Prince Caspian after Caspian asks if he could fight Miraz and avenge his father, Peter says,
Prince Caspian said:
We have seen that you are a king and a warrior, but he thinks of you as a kid.
Miraz raised Caspian, so he will always think of him as a kid. If you've raised someone since they were small, you kind of always think of them as small. My point being is that they don't say Caspian is a kid, but rather Miraz THINKS of Caspian as a kid.
Also in Chapter 8, I find this very interesting, after the Pevensies tell Trumpkin who they are, he says,
"The King, Trufflehunter, and Doctor Cornelius were expecting...help. To put it in another way, I think they'd been imagining you as great warriors. As it is- we're awfully fond of children and all that...."
I find it very interesting that he uses the pronoun
we're, the antecedent to that being
The King, Trufflehunter, and Doctor Cornelius. If Caspian (the King) is supposed to be a child or a kid, then why is he "fond of children"?
In chapter 12, the quote that Ben Barnes usually refers to, describes Caspian as "a boy about his (Peter's) own age". A boy could be a "youthful, male person" (according to the Free Online Dictionary). So we could assume that Caspian, is not being described as a kid, but rather as a youth, maybe even a naive youth.
Also, if Peter is let's say 15 in
Prince Caspian then Caspian, being "about his age", could very well be a couple of years older, so 17 would be a fairly accurate age to put Caspian in.
Also, some people may be biased, because we pretty much knew that Ben Barnes was quite a few years older than that before we really saw any clips. And I have to admit, he doesn't look 17 in some (or rather most) of the action clips that we've seen him in. But remember that those are for advertising, they are playing up his looks and a swashbuckler persona. This may come as a shock to you but they're doing this for profit. (surprise surprise)
But in the little that we've seen him in other parts, like the clip in Trufflehunter's cave, or even the clip in The Dancing Lawn. He does look like a youth.
Look at the two pictures below, and you can see that he could pass for a 17 year old.
What's really the difference between a 17 and a 25 year old, anyways? I don't really think there's much, there are some 17 year olds who look older and some 25 year olds who look younger. I recall one interview Ben Barnes had he said that all he had to do to look younger was shave twice a day, or something like that. So, there's really not THAT much of a difference.