No doubt you are faced with a dilemma. Is this relationship a serious one? How do he feel about you? Is joining the navy something you really want to do? Have you explored other career options? I suggest seeking the advice of a counselor at your school to help you address some career options.

I agree with pacorz that if you have already signed a contract you have little choice.  Once you have signed the paperwork, there is no backing out.  Not for the next four or five years at least.  If you have simply spoken with a recruiter then you still have some options.  At this point in your life, I would strongly encourage you not to base your life choices on a boy.  Over the next couple of years, you will both grow and change rapidly as you leave childhood behind and strike out on your own.  Sometimes these changes bring couples closer together and sometimes they drive them apart.  Base your life choices on what you want and what is best for you.  If he is truly meant to be your life partner, he will still be there.  

Have you officially signed up for the Navy? If you have, you may have no choice. The military is not high school, and once you have made a commitment, you can't just drop out if you change your mind. If you signed papers with a recruiter, you need to sit down and carefully read through and see what they say.

I think #2 has given you excellent advice. From both my personal life and from observing young people for many, many years, I honestly think that most life decisions made because of the location or wishes of a boyfriend/girlfriend are poor decisions. You need to take care of yourself, first and foremost. If your boyfriend really loves you he will support your decision and wait for you. If he does not, then he wasn't the right guy anyway.

I am going through a big possible change in my life right now involving my career path.  Ultimately, you have to think about what is most important to you now and in the future. 

I would say that now, you boyfriend is probably more important; however, in the future your career in the Navy is probably more important.  With that being said, if this guy is your true love, it might be a bigger part of the future than the Navy. 

Think long and hard about your priorities, where you see yourself in the future... and talk with your boyfriend.  Maybe he sees the relationship differently than you do. 

The French have a saying, "Dans le doute, abstien toi." That means, "When in doubt, don't do anything." I suggest that you enroll in college or junior college after you finish high school. A year of college will give you time to think things over and will make you more valuable as a potential sailor or civilian employee. It will also expose you to a lot of new ideas. A lot of colleges offer career counseling and testing. If you are still in doubt, take another year. You're young. You say you decided to go into the Navy but now you don't know if you still want to go. So you haven't really decided, have you? Just leave it that way for a while longer. A lot of decisions resolve themselves with time. Is the boyfriend the only factor in the equation? If you didn't have the boyfriend, would you definitely go into the Navy? What does he think about it?