Age chart for active duty and reserves^^^ You can still go active duty in either the Navy or the Army. If I had to choose between the two I would DEFINITELY choose the Navy. But, if you really want to be a marine you still have 1 more year to join the reserves. If I were in your position, I honestly would go active duty Navy and try to go DEVGRU (make a career out of it), rather than be a part time bad ass. Even though active duty USMC is where it's at. If you really wanted to be a Marine then you would have became one by now.