"'And what are you reading, Miss — ?' 'Oh! It is only a novel!' replies the young lady, while she lays down her book with affected indifference, or momentary shame. 'It is only Cecilia, or Camilla, or Belinda'; or, in short, only some work in which the greatest powers of the mind are displayed, in which the most thorough knowledge of human nature, the happiest delineation of its varieties, the liveliest effusions of wit and humour, are conveyed to the world in the best–chosen language."
In this part of the book, she is saying that people in her time think novels are not very serious, but why shouldn't she let her heroine read novels? She thinks novels are serious because she is writing one and also because she thinks they are a great way to learn about humans and what they are like.
I like this quote because Jane Austen loves novels like me.
But she hates gothic novels. She makes fun of them in this book.