It is normal to feel nervous before an important interview, but with the right preparation and mindset you can minimize such pre-interview jitters. It is expected by the interviewer that you do express some form of interest to work for the organization by having some basic information firmly etched in your mind. It is flattering if you can show some form of interest for the organization by having the right information ready whenever a question arises. Be prepared because obviously, interviewers will favor those who come prepared.