Writers tend to think about themselves a lot. This is not really a function strictly of ego; our characters are hybrid creatures, made of observations and instincts. So understanding our own personalities as well as those of people we see is, I can state unironically, a part of the job.
But there is a disconnect somewhere. I'm not sure I know myself all that well.
Don't get me wrong: I am not claiming to be oblivious to my own quirks and my thought processes. But the impressions that others have of me, when they are expressed, don't seem to line up with the ones I had formed on my own. And being the insecure type I am, I usually assume that the other people are closer to the truth than I am. (I don't when reading comments on web pages.)
I have been told, for example, that I am too self-deprecating. I see myself as just self-deprecating enough; I use it as a deflection from any perceived expression of ego. I'd hate to be seen as someone who thinks he's amazing.
Everyone has some self-delusion, I've decided. There isn't a person I know who doesn't harbor some deep-seated belief about him/herself that any casual observer would label as the complete opposite of the truth. Most of these misconceptions (if you choose to see them that way) are trivial. They're small or unimportant or both. But everybody has at least one.
I'm not sure what mine is, but I guarantee you it's there. If you know me fairly well, you probably have a few candidates you could nominate for my best self-delusion.
So the trick in writing characters, then, is to present the whole package. Give all the characters something of a muddled view of their own psychology. Sometimes you let the reader see it, and sometimes you don't, depending on the story. What's important is that the writer, being the observer and the omnipotent deity of the book's universe, sees the contradiction and chooses whether or not to expose it to serve the story.
Now, a first-person narrator like Alison Kerby probably isn't going to be hyper-aware of her own delusion. She can see it in others, but when concerning herself, it has to be brought to her attention. Most people, trying to get along or simply not all that concerned, probably won't confront a friend or relative with their misconeptions except under duress.
Luckily, fiction provides tons of opportunities for duress.
So if you know me pretty well and think I'll benefit from pointing out exactly where I'm wrong in my own assessment of me, feel free to let fly; I won't get mad. I might disagree, but I won't get mad. If you don't know me well, I'm willing to guess you won't care that much and, as a casual observer, will feel less inclined to bring up the subject. Probably just as well.
If we know each other and you'd like my assessment of your own misconceptions, rest assured that I probably won't have a really interesting answer. Writers observe, but we're not always great analysts.
But if you have ideas about Alison Kerby's wrongheaded beliefs about her behavior and her personality, I must ask that you please don't mention those to her face.
There are some things we authors like to reserve for ourselves.