That is a question I ask myself when I'm sometimes lost, or undecided. Even for teenagers who don't know what to do after school. To study or to work, but study where? These decisions are hard, and many don't know just yet.
I found that asking yourself "what I'm not?" and "what I don't do" can narrow the search field and put things in a more transparent route. Then combine that with fallowing your interests and curiosity, and it will lead you to answers, for some maybe even to a life goal.