As an old Army guy, my advice would be if you want to join the military, go ChAir Force. Rank is slow, but those guys live like kings!:mrgreen:
Fixed that for you!
Don't for get the option of joining the reserves or a Guard Unit. It will allow you to gain skills, maturity, responsibility, a side income, and even help pay for college if you so desire. I am not certain, but you may even be able to use the benfits to pay for a trade school as well.
What ever you do, don't forget to live life. Do not become fixated on a catastrophic collapse and forget to be young. You only get one shot at youth, don't let it pass you by. That being said, it's possible to enjoy being young and still have a plan.
With the simply stupid cost of a 4 year degree these days I am leaning toward recommending learning a skill/craft/trade that will be in demand, you enjoy doing, and you can get licensed/certified in a couple of years. You start earning much sooner than a kid who is racking up tens of thousands of dollars, or more, in loans, and you don't start life in a deep financial hole.
Save your money until you can afford quality gear that will last and not need to be replaced after moderate use. Take your time and build your preps slowly. Start out with a goal of 3 days of preps, then a week, then two weeks, etc, etc. Before you know it, you will be well on your way.
Always accept the opportunity to learn. It's awesome you have your Grandfather (saw it another post) to learn from. Pester him for knowledge, he will relish the opportunity to teach you. Don't forget to learn things such as mending garments, gardening, and how to can foods for long term storage either. Throw any concept of "that's womens's work" out the door right now, because it will possibly be your own young man's behind in need of those skills someday.
Oh, and Welcome to the site from blistering hot Texas!