In the meantime, she had to construct as convincing a lie as possible, ahead of time, to tell the people at Durmstrang. She'd gone to some effort to compose one that was convincing and self-consistent, and contained some kernels of truth. For one thing, she wasn't going to try to convince anyone that her "adoptive" parents were wizards; that wouldn't hold up to any close scrutiny. Instead, if all went well, other wizards would collaborate in pretending to her parents that nothing strange was happening at all. (She suspected that the sort of pureblood supremacists who ran Durmstrang would probably not have any ethical objection to lying to Muggles. After all, as far as they were concerned, Muggles weren't people.) And if they thought she was pureblood, she would (hopefully) be able to get through her schooling without anyone trying to kill her. Which was, of course, the point.