...Catherine is consciously doing, or is this more ironic hyperbole by the author? NA1 and NA2 to the contrary, the text as I read it (so far, at least) gives no indication that Catherine has read any Gothic novels. In fact it gives no indication that she sees herself as anything more than a normal girl who, at fifteen, suddenly wants to fit in better; so she stops rolling down hills, acts more ladylike, washes more diligently, pays more attention to her clothes and grooming, tries to learn a few quotes to impress (we do not know that quotes listed by the author are representative of what Catherine learned or selected to support the author's spin), and starts to look forward to local balls to meet (and dance with) other people her age.
To me the mission to be a heroine is completely superimposed upon someone who is trying to be a sought-after young lady; it is a reinterpretation superimposed on her by the author as a humorous device.