I think about this question all of the time.
Even after almost thirty years, I still don't have a concrete answer.
Let me rephrase that: I still don't have one answer. At this point, I'm a designer, writer, founder, and a self-proclaimed "productive fumbler."
After all, there are so many possibilities. Why choose just one?
Because society tells us to? Because that's why our parents did?
I don't buy it.
Life is too short to pigeonhole yourself into one career and then call it quits.
Whether we realize it or not, we're all so multi-faceted. We're a complicated mix of strengths, weaknesses, interests, talents, and dreams that can't easily be defined using one word.
At the same time, there is something to be said for being patient while you try and answer the above question. Give yourself time to fully commit to a project.
Otherwise, you'll be asking yourself this question for the rest of your life...and you won't have an answer.