Starting from bootcamp, expect hell. Internal fortitude is what you will be tested on as well as knowing and applying the buddy system. If you have not learned any form of discipline before hand, you will learn fast. If you can endure all that physical pain and mental strain and finally earn your title, then know youmade it. After that, it's fun and many opportunties to excel or mess up. A clean record and lots of "brown nosing", moves you up otherwise, 4 yrs may just be long enough.