I noticed that in the book Charlotte's Web, a lot of characters seem to get older and change as the story goes on. In the beginning of the book, Charlotte was healthy and seemed average but by the end of the book she was rundown and weak and she died. I guess that E.B. White is trying to make the book realistic. In my own life, my great-grandparents used to play games with me when I was 4, but a few years later they had Alzheimer's Disease and hardly recognized me. Things will always change, some are good some are bad.
Another example of this is how Wilbur grew up. At first he used to be like a child, always needing a mother figure (ex. Fern and Charlotte.) Now, at the end of the book, Wilbur has finally grown up. He's kind of like a child who turned into an adult.
Another person who changed a lot was Fern. At the beginning of the book, all she cared about was saving Wilbur and then taking care of him. She would visit him at her uncle's farm every day. However, towards the end of the book, she started to go out and do more things with her friends and she didn't even stay to see Wilbur win a big prize at the county fair. As people get older, their interests change.
I think that E.B. White wanted to make her book realistic and not just for little kids. I think that the message that E.B. White is trying to send is that as people get older they change their interests, their personalities and they change physically too. Overall, everyone will change for better or for worse.