"Oh! You are a great deal too apt, you know, to like people in general."

I truly think that Lizzy is only needling Jane about her tendancy to think highly of anyone and everyone she meets. A few sentences on she is asking about how well Jane likes Bingley's sisters. Nowhere is it implied that Jane and Bingley were in "love at first sight" - it is not until Chapter Six that Lizzy becomes even reasonably certain that Jane was "yielding to the preference" and was "in a way to be very much in love" and this was after it is implied that they have met several times.