One of the things I was told early on when I started writing was that a good chunk of my editing would focus on the beginning parts of my manuscript. Writing an entire novel takes a long time several things can happen to you, the writer, during that time. Finding your voice is a big thing. By the end of the novel, you understand these characters and you understand how you want to convey the story to your audience. It's something that comes to you with time and with practice. That means, inevitably, the characters you are writing in the beginning are not the same as the ones you are writing at the end.
Now when I say that, I'm not talking about the metaphorical, personality changes that a character is supposed to go through across the arc of a narrative. That's a natural progression that a character is supposed to make and you should be directly responsible for that. The change I'm referring to is the unintentional change that comes as you get to understand the character you're writing. Maybe in the first chapter you have it set that your protagonist stutters when they get nervous. Chapter one might not have enough opportunities to show this off, so you work it in, but, months go by, maybe years, and your writing style and ideas about the story and the character have changed. You've seen them in action now and it makes more sense that they don't stutter. Maybe it makes more sense that they're direct about criticisms they have.
I know that when writing Jonathan, I had a very "good boy" church type in mind, but that was changed by the end of the novel. The Jonathan that ends the novel is the real Jonathan, the one I had to write and write and write to find. Now it's my job to go back to the beginning and fix his character and keep him in line with his true nature. I understand that I need to make sure his character changes and adapts, but it still needs to be true to who Jonathan is, and that was only something I could learn by writing him.
Don't forget to be awesome!
Keep your eyes open for my debut novel, The Paladin.