As a prior Marine, I can honestly say it is very unlikely you can join with a GED. There is a whole new standard recently put into place that is making it very hard to get into the Marines. Most recruiters are only allowed about one GED per so many regular high school applicants. You can go to college and get 12 credits and the GED factor is no longer considered. Good luck and kudos for wanting to serve in the best branch of the US military.