Yeah. The main character works for an interdimensional organization that thinks mages are extremely rare--there've been, as far as they know, two good mages in the last 100 years or so. The main character, Nanoha, also recently suffered a massive injury that means if she uses a lot of magic, she could lose her ability to use it completely.

Suddenly, a guy on a broom flies up to her and wants her to teach at his magic school, in a subject she knows nothing about, when she is eleven years old, has school and training for the aforementioned agency, and CAN"T USE A TON OF MAGIC. AS IN, WHAT HOGWARTS TEACHES. AT A SCHOOL THAT SHOULD NOT EXIST. See any problems here? I don't think Dumbledore even explains what Hogwarts IS.

Oh, and Nanoha's family tree is a teeny-bit small. See, her dad is a retired ninja bodyguard, who quit the business, married, and changed his name after most of his family died. His only relative, other than his children, is his sister, whose husband died and who works at an antiterrorist organization in China, I think. This fic says that Snape is Nanoha's UNCLE. HE SHOULD BE A NINJA AND DEAD.