"I don't think, sir, you have a right to command me, merely because you are older than I, or because you have seen more of the world than I have; your claim to superiority depends on the use you have made of your time and experience."
First of all, there is no direct textual reference to class here at all. Jane mentions only age and worldly experience: "older than I ... seen more of the world." Nor does the author through Jane Eyre bring gender directly into this comment, although both may be said to be indirectly referenced as it may be said that upper class Victorian men had the freedom and means to travel at will while financially dependent, young, unmarried women had no such freedom.
Secondly, the issues directly brought forward in this quote are the definition and meaning of superiority and the nature of a woman's role as a governess in a household, which seems a rather narrow issue to bring forward but one of experiential importance to the Bronte sisters and one which indirectly reflects on the issues of gender, class, and servitude.
The first consideration of theme is that Bronte, through Jane, defines superiority as an inner characteristic independent of travel, wealth (assuming wealth is needed for independence and travel), age and (indirectly referenced) gender as men had freedom to travel that women in general did not have. She defines superiority as derived from what has been done with time and experience. These are elements that are universal and the common province of everyone and anyone; even the most impoverished and disadvantaged have time and experience. Bronte and Jane Eyre thus separate superiority entirely from gender, class, age, privilege and wealth
The second consideration of theme is that the employment of a young women as governess in a household gives her equality of class, superiority, independent individualism, and independence of thought. (1) As a governess, Jane does not scruple to speak up independently to Rochester nor to correct and reprimand him ("I don't think, sir, you have a right") nor to instruct him ("claim to superiority depends on the use you have made of your time and experience") nor to thereby equate herself with him. (2) Jane thus equates herself with his social class and confirms for herself personal independence and independent dignity (even though she lacks monetary independence) along with the independent authority to have and express without fear independent thought and action.
Therefore, though the themes touch indirectly on class and gender, the direct thematic issues brought forth in the quotation are (1) the definition of superiority and (2) the definition of the position of a young, unmarried woman employed in a household as governess.