The first step would be to take interest and aptitude tesst to determine what career fields might be suitable for your interests and aptitude. You could then to talk to the Marine recruiter in your area to see how you might be able to apply these to the Marines and get further training after high school at their expense. They will train you during your tour of duty to do a job for them. You may decide to make the Marines a career and spend 20 years there, or you may choose to leave after your first tour. If you choose to leave, you can go to college on the GI bill to further your career training if necessary. You would only want to go to ROTC if you want to become an officer, but you can enter the Marines and get their training and complete college on the GI bill when you get out. These are things you can discuss with the recruiter. It would also be helpful to go to the alumni officer of your high school to talk with graduates who are in the Marines or have been in the Marines to get information from them. Send thank you notes to helpful people. I would interested in helping further if I can. Good Luck!