This went down the drain fast.
Everyone is shown to be braindead. First, a weirdo introduces herself and nothing comes of it. Even modern tropes would have her be looked at like she's crazy.
She floats in the air and no one sees her, she casts visible magic in front of the teacher and others and nobody sees it. The MC suddenly cares about protecting her and says what was a tired cliched line 15-20 years ago to the character that has powerful magic and essentially sees him as something to toy with.
This is fucking retarded. Was the author pushed by editors to add such crap or is this the author's own competency level?