Valentia, there are many answers to this question. How are you paying for school currently? If you are taking out loans, it could be beneficial to join and utilize tuition assistance to help pay for school. There are programs that will pay your way through med school, if you would rather that. It's called HPSP. You could join the Reserves, allowing you to continue through school, but utilize tuition assistance and beginning your career in the Navy. I would recommend talking to your nearest Navy Recruiter to really dive into benefits of your options.
It depends on how soon you want to get into the workforce and your finances and career intentions. If you want to get right to work and take classes while earning a fulltime paycheck and serving in the Navy then enlist now. However if you want to pay for your tuition yourself or through other scholarships, then continue your studies and keep in touch with the Navy recruiters to make sure your college is accredited and meets Navy requirements. I agree with James in that you should contact a Navy recruiter to find out what options are available based on your test scores and career goals.