Awesome!!!! Thank you for your interest in joining the worlds greatest Navy. I myself was active duty for 15 years, My wife was for 20 and my brother for 22. So as you can see I am really passionate about this. To answer your question the classes you would need to take honestly would depend on what you want to do in the Navy. Keep in mind that there are tons of career choices. Cyber Security, Legal, Cooks, to weapons. The possibilities are endless. I would suggest that you do as well as you can on the ASVAB test which is the Armed Services Vocational Aptitude Battery. It is used to test you and discover the jobs you would be best suited for. Scoring high gets you more options so you really want to focus on that. Online there are study guides that will give you an idea what you should be looking for in term of study. 4tests.com is one site you may want to look at. Hopefully this helps you and keep in mind that you should look at a job that you can transition to once you decide to leave military life. The military provides all the training you need for your future job and often that will give you all the skills you need once you decide to become a civilian again. Good luck.