Jane herself was raised in a home where many boys were staying as pupils with her father as their teacher. There was an opportunity there for Jane and her sister Cassandra to become well-educated, and they did. They obviously read a lot. Jane obviously has a command of grammar and had an interest in many subjects. Jane would know that it was possible for two sisters living in a home where there was a school to become educated if they chose. Anne and Lucy evidently did not care to exert themselves in this way.