Military Women!

I'm almost 17 & in my junior year of high school. I've really been considering the military over the past few months, but I find it very intimidating. If I do go in I would want to do my basic next summer and then come back to highschool and do my AIT? The next year. I have a few questions though. 
•How hard is basic?
•What was the hardest part?
•I want to be an M.D., anything i can do within the military to help me?