Hmm... Before going to the tea party, she describes herself as the daughter of a marquis, but then she introduces herself as the daughter of a duke to Bernhardt. Which one is it? A pretty huge difference there. A duke is, after all, directly beneath the royals (if there's no grand duke), typically governs a large provinces with many lesser nobles under him.
In either case, it's pretty funny for her to consider herself a mob character when she's in such a highly privileged position. But I guess it's legit as far as the game was concerned.