Don't worry about it. My roommate just graduated and didn't get her driver's license 'til March of this year. I also had a friend who got his 2 deg year. He had a Japanese license but no American one. You can just find rides with other people, not a big deal.
You will have a military ID. I'm not sure how that will work on I-Day, but I'm assuming if you have a birth certificate, you'll be fine?