I guess, for me, if this was an isolated incident, then I would put it down to her being human. We all make mistakes. I forget things like this sometimes, forget to ask how people are, their relatives, their pets, etc, and people do it to me. Its not necessarily a personal thing, its just being human.
However, if she is being this self centred all the time, is this someone you want to be around? If not, then what you need to do is doing something that will help you feel better about the situation, such as writing her a letter/e-mail to tell her how you feel, or distancing yourself from her. Just don't let her failings as a person impact too much on your life. You have enough going on without being angry at someone who doesn't deserve your thought waves.