Looks like the real problem is that she has a fucking worthless teacher who's unable to explain things properly and clearly to her, and her other pupil for that matter, too.
She is stupid. Her master time and time tells her that her magic doesn't work the normal way, but instead of living with her master, she ran away and tried to live without using her talent.
She just doesn't think highly of her skill at all, even after saving those people, she just walk away instead asking for food.
This is very cute manga, but I honestly doubt if this manga can be different than other manga because MC is so stupid. She probably get some help and regcornize of her skill later on.