@puzzled - As far as PMing you may not have enough posts yet.
Navy requires that you take English Composition. If that's the English course you are dropping, and it's usually taken freshman year, I would recommend against it. English composition will help you succeed in all your other courses. If you can't write cogently, you cannot succeed in college (OK, I'm using a broad brush). If you must drop a course I'm sure there are others you can consider dropping.
Also, keep in mind that your first semester in NROTC is probably the easiest semester you will have in NROTC. Over time your responsibilities as a leader will increase, and consume more of your time. By senior year I think DS was spending about 20 hours a week on NROTC. I often wondered if he was majoring in history or NROTC. You'll also be taking your easiest college courses at this time. On the other hand, I'm also a firm believer in only taking 15 or 16 hours first semester of freshman year. You will already have plenty to adjust to going off to college and enrolling in NROTC. Wait until second semester to tackle so many credit hours.
Personally I alternated... 15 hours one semester and 18 to 21 the next. With credits I was awarded for courses I tested out of, senior year I was able to coast with only 12 hours each semester.
I'm sure I'm not any help discussing some of the angles you should consider... but you need to do so. Good luck on your decision.