don't forget she grew up passively charming everyone around her. she had never experienced being wrong. that's why she didn't understand when the dragons are telling her something else that she does not believes in. the pope/priest are partly to blame for feeding her false information.
for those that enjoy this, there is a separate story based on the same world. titled "我才不是魔法少女" roughly translate to "I'm not magical girl" characters will sometimes mention zero. that is if you don't mind the gender bend genre.