USNA is not unfamiliar with the variations on grading scale, and that is one of the reasons SAT/ACT scores are used as initial screening tools, so work to get your best possible scores on one or both of those exams. (Personally, I recommend that prospective candidates start taking those exams during their sophomore years, and take both exams at least once so you will know which exam is more favorable to you.)
Items taken into consideration will include courses taken and at which level of difficulty, grades/grading system, number of students, number of graduates who go to college, any recent grads become midshipmen and how did they fare, etc. IE, more angles than you may have imagined and some you haven't thought of - yet.
Big clue - give it your absolute best shot going forward and you won't have to apologize nor will you be sitting on your front porch 30 years from now thinking "... if only I had studied harder, or done this or that differently..." One other clue: don't procrastinate, just get'er done! Best wishes to you!