You could hear anytime once your application is complete and your first semester college grades are received. Reapplicant or first timer, most hear in the mid/late Jan to mid-March timeframe. As you know USNA doesn’t release their WCS formula, but I am sure they have this factored in for reaaplicants. As far as I know, your intended major does not impact your admissions. I would think the best thing to help yourself would be taking a Plebe like schedule and knocking it out of the park and a positive endorsement from your leadership in NROTC.