Once in a lifetime job opportunity?

Ok now get this I could get a job that could gurrantee me up to 500 a week and its workin on a cruise ship now I have a g/f here I have nothin else to hold me back but her. She put up an awfull fight to try and get me to stay here but in the end just said its what you want and said go for it. Now at the end of it she told me that don't expect me to be here after tellin me I better come back and get her. I was kind of freaked out that she would say something like that I don't know I really want to go but she's making it so hard to decide. What should I do I mean this job could make me some money and get me back in track with my life and I could also make new friends and meet new people I mean DAM its a cruise boat lol what more could you ask for. By the way me and my g/f have been dating only 4 months