It does seem kind of ridiculous pollyplummer that Susan would make such a choice. I believe that Lewis was mirroring what is said in the Bible that some people that we would expect to get in to heaven don't (i.e. Susan) and that some people that we didn't expect at all to get into Heaven do (i.e. Emeth). That was kind of a side note but I just thought I would mention it.

Now on to an explanation of why. It is said in the book that Susan was a good deal too keen on growing up and that her head carried fancies of nylons and makeup ext. That is a nice way of saying that she was a flirt and that her head was too caught up in being one that she forsook Narnia (for Narnia wasn't built on such principles) for her idle fancies. It's very sad I know, and from our perceptive rather stupid, but I think that it is the truth.

I suppose you're right - Susan probabbly is meant to be something of a lesson for us to demonstrate that not everyone who you think will get into heaven actually will! I still just find it so hard to believe she could be so stupid to pass up being a Queen to be a shallow flirt. Unless she really believed that the Queen Narnian part of her life was over - in which case she totally missed Aslan's message - which is probably quite a good reason for her not getting into Aslan's country in the end (unless she's given another chance later) She was given so many opportunities and yet she doesn't understand!

It all boils down to three words, lack of faith. If Susan had had more faith I don't think she would have been that stupid but her lack thereof in PC means that she probably had a lack from then onward too. Put that together with her fanciful allusions of wanting "grow up" then you get a recipe for disaster.

How did Susan loose faith? Well I think that she never really recovered from leaving Narnia the first time. After she was "kicked out" the second time, which is probably how she saw it, it was too much for her and therefore she kind of lived in denial from then onward.

Aslan's point at the end, when saying why Peter and Susan couldn't come back be that she and Peter had learned all they could from Narnia but judging from her behaviour for most of the book, she didn't appear to have learned too much! Also she must have completely missed or ignored the point of becoming close to Aslan in her own world.

You're right, Susan apparently did not learn everything she should have. But, there comes a point where the teacher is done teaching and the student is left on their own and it is entirely up to the student if they are going to use what they have learned or not. Susan always had a hard time believing in Narnia, after she knew she was never going back, it became easier for her to believe there never was such a place. A magical country did not fit in to her ideas and way of thinking. Also, I just checked the book, and there is no mention of them having learned everything they could. Peter only says that he and Susan are getting too old. In VDT, Aslan tells Lucy and Edmund that they must become closer to their own world. That might play a part in Peter and Susan's last time.
Yes, I think she also missed the point of becoming close to Aslan in our world. Perhaps that was another reason she rejected Narnia.

In a couple of C.S.Lewis' letters he mentions Susan. You can find these in the Letters to Childrenbook.
"Peter gets back to Narnia.....I'm afraid Susan does not. Haven't you noticed in the two you have read that she is rather fond of being too grownup. I am sorry to say that side of her got stronger and she forgot about Narnia."

"The books don't tell us what happened to Susan. She is left alive in this world at the end, having by then turned into a rather silly, conceited young woman. But there is plenty of time for her to mend, and perhaps she will get into Aslan's country in the end--in her own way. I think whatever she had seen in Narnia she could(if she was the sort that wanted to) persuade herself, as she grew up, that it was 'all nonsense.'"

Well, also, susan is her own person and being so, is able to make her own choices, rather we like her decision or not, but that still doesn't make her a bad person.. she just has her own ways of living, as we all do..

I honestly think that aslan will accept her into his country when her time comes.. but we don't even know how she reacted when she found out about the train wreck, either.. maybe that also brought about another change in her that we didn't see..

and well, she just doesn't seem to be the fairy tale type person.. some aren't.. some do consider narnia to be nothing more than a fairy tale and brush it aside, as susan seemed to.. they'd rather live life in the reality that surrounds them; rather than dream of a world they know they'll never get to because they believe it doesn't exist..

I don't think susan is a horrible person because of her choices she's made, she just desided to live her life in a way that some people disagree with and dislike her for.. and yes, there are people who dislike/resent her because she no longer cares for narnia.. as far as we know..

I hated it that Susan was no longer a friend of Narnia. She was my favorite character until then.

In the Last Battle, Eustace says

Whenever you've tried to get her to come and talk about Narnia or do anything abou Narnia she says, 'What wonderful memories you have! Fancy your still thinking about all those funny games we used o play when we were children.'

I think that Susan came back and felt awkward coming back. Maybe she tried to tell people about it and they thought she was weird or making up stories. Then she persuaded herself that she dreamed it or that they were just making it up because she wanted to be normal. It's easier to be normal.

It all comes down to this: Susan no longer had faith like a child.
I feel a bit cruel because I never questioned why Susan wasn't in the New Narnia. It just seemed natural for her character.

My cousin Malina suggested that Susan didn't believe anymore because she might've lost her childish imagination to a more mature adult. I'm pretty sure that's why.

Her child like imagination is part of it but it is more her childlike trust that is the issue. Lucy's character is such that she puts her trust in Aslan in this way: "he said it so I believe it". Susan doesn't have that quality and as consequence succumbs fears and insecurities about Aslan's intentionality to her.

Susan has lost faith. It happens a lot in our world as well: people grow up knowing Christ and then grow into their own person and lose faith as time goes on. Or a person has all evidence of truth but fails to really be devoted to it.

Susan had lost her faith. She had never really trusted Aslan much, and therefore when she had to leave Narnia and could never come back, she probably felt rather upset about it. And then she was always interested in all that "girly" stuff: lipstick, makeup, clothes, etc. She probably tried to forget Narnia by telling herself that it was a story for children, and then trying to grow up too fast.

My cousin Malina suggested that Susan didn't believe anymore because she might've lost her childish imagination to a more mature adult. I'm pretty sure that's why.

I don't think so. Polly says she wishes Susan "would grow up." I think it was C.S.Lewis who said that as he got older he put away childish things, including the fear of being seen as childish. (I think that's how it goes. Anyway, that's the jist of it) Susan is a young adult who wants to remove herself from anything that has to do with her childhood. She wants to be viewed as grown-up and mature. Even if she really isn't. She tried to grow up too fast. She thought magical worlds with talking lions, no matter how wonderful they may be, belonged in a child's fairy tale. And so as she tried to grow up she shoved aside anything that held her back.

I agree with jadis of narnia. And I like to think she came to Narnia later. Maybe she was kind of like his Goddaughter Lucy who CS Lewis wote LWW to.

Remember the Bible quote: "Amen I say to you, whosoever shall not receive the kingdom of God as a little child, shall not enter into it." (Mark, 10:15)?

I think that's pretty much the reason Susan didn't come back.

Boys, parties, and fashion are very real things. A magical land you visited in childhood years (and the lessons you learned there) might fade if you got too caught up in material things and tried to rationalize your new state of mind by pushing away the miracles that happened to you.

If Susan had kept her faith she would have seen the real logic of the matter, with the piercing perspective of a child. Aslan did exist and being good and loving God are the most important things on earth-- on any earth.