Leaving for the navy in a month... Relationship/other questions?

I leave for BC Dec. 9th to be an ET (AECF) in Great Lakes, my A school is also there. I am currently in a relationship that ive been in for over 3 years now. My girlfriend left for college about a month and a half ago and its really been hard on me. we are both very young 19 and 21. We have been through literally everything you can think of and still fight to stay together to this day. Im just wondering if its going to be easier while im in A school. Also where exactly will i be living while in A school and can she come visit me and stay with me that sort of thing. I mean our relationship isint the easiest thing at all right now and i really am worried that we wont be together and i really want to. I want to marry this girl if we can make it through the first year of me being in the navy. Also how does that work, and how hard is it to get married while in the Navy expecially if shes still in college. sorry for all the questions im just really scared cuz i love her to death