I do not think JA is concerned about the perception of "her work" because when she wrote NA she did not have a body of published work (and I do not think this would have been written in late in her life).

So rather than being a self-conscious reference to her own style, I think the dichotomy between what Catherine is (as you describe her) and what JA says she is not (or implies she ought to be by implying she is not) is all about Catherine (and about the novels she is parodying).