End of Prince Caspian

So, I know I should have posted on the ending of our last book sooner, since I finished it about 3 weeks ago. I have already returned it to the library and can't remember the ending as well now as I used to, but I will comment on what I can remember. Obviously, a great book. I enjoyed reading it again since I really didn't remember it that well, so now I am feeling pretty good for the movie coming out (very soon!). One question, near the end of the book, when Peter and Susan say that they will not be returning to Narnia because they are getting too old, and Lucy expresses sadness for them, why does Peter say it is okay and Lucy will understand when she gets a little older? I don't understand why it wouldn't be as enjoyable for them just because Peter and Susan are growing up. Is it because Narnia is a place of innocence and Peter and Susan are losing theirs? Please let me know if you have any theories. Also, I thought it was interesting that Lewis put some of those other gods in there, like Baccus and the other one (can't remember the name, probably would have been good to have the book in front of me), especially because those are ones that are historically kind of racey. But obviously Lewis is showing that Aslan is above everyone and over everyone. I definitely like the idea of Jesus as a lion, it shows a lot of power that I think we can forget sometimes since we see Jesus as a buddy. Well, I think that is about all I wanted to say, please answer my questions if you can! (except Sarah who I don't think read the book.) I can't wait to see the movie, I think this should translate well into a movie, lots of fighting and battles which I like! Good book.