I know Mids who majored in Marine Engineering Systems who went SWO, and I know Mids who majored in Marine Transportation (straight deck) who became seabees. Active duty does not necessarily care about what classes you are taking. You have Mids at USNA majoring in History going Subs, SWO, Aviation, etc. You should choose your major based not only on your interests, but your strengths. Keep in mind that 90%+ mids at USMMA change their minds about what they wanna do post-graduation, usually more than once. In terms of getting your GPA as high as you can, which is what Active Duty billets look at (among some other things), the understanding is that the Marine Transportation major (straight deck) is the way to go. Keep your mind open though.