[quote=Balance]
Also, I'm well is grammatically incorrect :P Unless you're saying you are healthy and fit. Then it's fine. But that's not an answer to "How are you?" However, you can say "I'm doing well." "I'm good" is technically an answer to the question "Are you a good person?" since good means "morally correct".
[/quote]

Not quite. "I'm good," in the sense of morality is little used, and makes no sense in the given situation. "I'm doing well," in accordance to the fact that she isn't sick, nor in any kind of peril, is the grammatically correct road.