There are a lot of stories just like this where MCs are basing their judgment solely based on the novel they read in past life and held the real-life charas accountable for things they didn't even do and might not do. In other stories, such point was at least loosely reasonable and the matter at hand usually just involves romance.
This?
She flat out reject an offer that will obviously help her and her father much, much better, is a total nonsense to me. What if she completely turned down Ignis's offer, then her father ran out again and at that chance, got himself killed?
If she didn't want to die she could have found a lot of ways other than not staying beside Ignis. Maybe be his adviser since you rely on the "fixed future" so much. Sheeeeeeeesh.