The restricted section was by far the most interesting part of the library, mainly because it contained all the rare, old books that can't be easily found anywhere else. Of course, she knew that she wouldn't be able to find the things that truly interested her- that being the truly dark, horrible side of magic that people generally didn't want to explore- though she found that the restricted section did provide a good basis for some topics that she would be able to further research outside of school, if needed.
She left dinner a little early that night, making her way to the library at a time where most people would be occupied with eating- presumably including the librarian. She'd be able to walk right in, no questions asked. And that's exactly what she did, making sure to close the door behind her before she went looking through some books that sparked her interest.