Even officers, who have to have a college degree, get trained heavily in leadership and the specifics of their job (surface warfare, pilots, submariners, etc.)
The number one thing that will make joining easier is getting in shape. Push-ups, sit-ups, pull-ups, and running. Do those until they're like breathing and you'll be amazed how much more your leadership will warm up to you since nowadays, physical fitness is declining among the ranks. Good luck!
Mitchell recommends the following next steps:
- Decide what you want to do specifically
- Get a baseline knowledge in that field
- Get out there and run!