Well best of luck to ya. Been through it myself. It'll scare you at first, but then it gets routine, just like anything else. When they ask for people for ships company, volunteer for it!
In gerneral, since you haven't posted what your 'A' school is going to be, I assume you are undesignated striker? if so, well...try for the smaller boats. The carriers have so many people, seriously, like a third world slum, both in density, and in hygeine.....Also, LOCK YOUR STUFF!! Again, due to the huge amount of people on the larger ships, theft is a serious problem. Always lock your stuff up, EVERYTHING! ( seen underwear get stolen before...)
Pack more socks and underwear than you think you need, then get more. Also, small plastic containers, and ramen noodles. have folks mail you more. This'll save your life out to sea, unless you wind up being a cook.
Almost forgot, one last thing...don't lock your knees standing at attention. You will pass out, and you will fall face first.
Finally, "shipmate" is a derogatory term, don't let anyone fool you. The only people that use "shipmate" are a-holes and diggits.