Lots of people do. They take the courses they need to take to prepare for the college degree(s) they want. A fair number plan to do what one or both of their parents did–law school, med school, sales, science, the military. And, I’m not counting the jobs people want when they’re kids; in my era, it was often a doctor, a policeman officer, or a firefighter.
From time to time, people on Facebook ask questions like, “How close is your career to the one you wanted as a high school student.” My answer is a rare one because I say, “It’s the same.” What about you? Did you always know what you wanted to do? If so, did you end up doing it?

There have been times when I wanted to be a clinical psychologist (college degrees Radio/TV and Journalism didn’t prepare me for that) National Park Ranger (NPS was looking for people with biology or law enforcement backgrounds when I inquired), passenger railroad engineer (AMTRAK killed that dream even though I have run a locomotive).
At the times when I was looking, magazines were always in the middle of cutting back on their staff and newspapers were paying poverty wages for beginning reporters even though I had a lot of newspaper credits from news releases written while in the Navy.
Oddly enough, I earned most of my income over the years from technical writing and corporate communications articles. Like my wife, I learned how to write code as well as the manuals that accompanied the applications that grew out of that code. Several computer companies on my resume wondered why, as a technical writer, I caught more programming bugs than those hired to test the programs. My answer was simple: as a writer, I loved the “what if?” game. When going through a new program, I always thought, “What will happen if I do this?” Of course, “this” was something neither the programmers nor testers anticipated, so they didn’t find the weak areas in the code. Hahaha–a good old liberal arts education was actually good for something.
However, by the time those Facebook career questions came along, the corporate jobs were long gone, and–finally–I was doing full time what I wanted to end up doing when I was in school. Most of us who write, follow a twisted route of blind alleys and dead-end streets to get there.
Did you follow that kind of route, first one thing and then another, and then suddenly a side street you never knew about turned into an avocation and then a career? A lot of us have been there and done that and wondered just where our careers were going, if anywhere.