Naval Academy grades?

I've been trying to get into the Naval Academy, and would like to know if the fact I made a 79 in honors chemistry will inhibit me going. I've taken all honors and advanced placement classes, made mostly A's, two or three B's, and did pretty well on my PSAT, so I'm planning on getting a good score when I take the SAT next year. Vice president for two years and president for one of the student council, soccer team (probably going to be captain next year), I volunteer to coach youth soccer on a base near my house and work for MWR. How severely will a high 'C' hold me back?