Welcome aboard Tim. Even though you might not be excited about early retirement at present (and understandably so), the fact that you are thinking ahead and recognize that it eventually will be an important issue puts you leagues ahead of others who may be in your situation.
In my view, the two most important things you can do now are
1.) Live below your means -- it is only by leaving yourself a financial cushion that you will be able to meet the exigencies that will almost certainly come your way, as well as have anything available for saving and investment.
2.) Develop a regular savings plan. If the military pay system resembles what I left 23 years ago, allotments make this a relatively painless process. The TSP did not exist when I was in, so I will leave that to others for advice.
While you are doing the above and building up your emergency fund, you should
3) Learn much as you can about investing. This thread from the Early Retirement FAQ's subforum will help -- An updated FIRE recommended reading list (with a military twist)
Some other random thoughts that may prove useful:
If you haven't got USAA auto insurance, check them out here https://www.usaa.com/inet/ent_logon/Logon
You will not find cheaper insurance and the service is excellent. As an investment manager/mutual fund company -- not so much
And on that subject, if you ever come across an "investment" outfit known as First Command, run away as fast as you can.
You should also start an account at Navy Federal Credit Union (NFCU). Yes, Army personnel may be members. https://www.navyfcu.org/
You are starting in on a honorable profession, and I wish you and your bride-to-be the very best.