Anyone's wondering what's up in the first panel it's a reference when in episode 8 he reveals that all Puella Magi becomes witches eventually. Nanoha is correcting that, which should happen...
Therefore, it's logical for those of you who will grow into Witches(Magical Women) to be referred to as Magical Girls.In this country, females who are not yet mature are called "girls", right?Sorry, that's a wrong answer. It's fine for Magical Girls to stay as Magical Girls."Magical Chronicle"? What's that? (Says Demon King)