if you're unsure what to do with your life, either going back to school to study something or finding a job, why not consider the military?
you won't know for sure if you're qualified medically and legally (they can permit some waivers for issues), but you can browse the branches websites to see what they offer. if you have a college degree, you could consider trying for officer training, otherwise, you'll be an enlisted soldier.
they will pay to train you and help you gain work experience. they have jobs besides combat related, that range from IT, to health care, administrative, logistics, transport, intel, and more. each branch offers a range a jobs, so see what each one has - marines, army, air force, navy and coast guard. your first contract will be four to six years depending on the job, and you'll have opportunities for travel, and education, along with meeting new people, and potentially a spouse or girl friend. depending on the base, they usually have activities for personnel to just sign up and take a trip in their off time or other group activities.
if you're still interested, see a recruiter. see one from each branch if you're unsure which to join. bring someone with you for moral support if you need it. they can ask questions too you might not have thought of, but it's ultimately your decision to join.
at the recruiters office, they will have you take an ASVAB test, which is basic high school knowledge to determine if you're qualified to join, along with medically and legally. the one at the recruiter's office is a practice test for them to gauge, but there are study books in local libraries and books stores. one's called ASVAB for dummies, among others. it's a good idea to freshen up on that if you didn't do well in high school, even if you did, this focuses on questions and areas covered in the ASVAB. the better the score will give you more job options, usually. you'll pick your job at MEPS if you enlist, that's where you also get your final physical before going to basic.
at the recruiters office, they will tell you all the steps in order before signing or agreeing anything to you to let you know what happens next.
good luck.