Join the Army after High school?

I want to know what are the pros and cons of joining straight after high school. I want to become a Health Care Specialist. Should I go to college before I join or will the military pay for my schooling? I am currently entering my freshman year, and I really do have my heart set on doing thing. I just want to know from a person who has experience in this or any advice for me. I would love to know anything and everything. And what classes I should look into and take to get me in a good position for this career.