How many of the things you do could be described with this statement?
I can describe so much of my life as things I didn’t expect to be doing. Some are things I aspired to, but that came into my life unexpectedly. (Directing Shades of Blue!) Some are things I never looked for but love doing. (Writing here every day! Being an at-home dad!) Some are things related to my passions but that I evolved into loving. (Directing the Aces!)
Rather than approaching life by saying, “I am preparing for this job,” I think most people would be better served by preparing to be ready for whatever life brings. The jobs will change, and they will be unexpected, and so there’s no use or even possibility of preparing for them. Instead focus on developing curiosity, creativity, general knowledge, and the ability to connect the dots between different ideas. Then, no matter what unexpected job comes your way, you’re ready to succeed.