I never had to choose a subject, my subject rather chose me ~ Ernest Hemingway
Once your dream journey is revealed, I think this quote makes the most sense. Once you find yourself doing what you're supposed to be doing with your life, you figure out that it chose you.
Once I set a goal to write a novel, I began searching for a topic. I knew I wanted to write historical fiction and then when I was reading a historical fiction novel, my premise came to me. The premise for my second novel came to me at church one day. I don't know how or why I was thinking about a scene from a movie, but the music inspired my brain to come up with the premise of the my second novel.
So if you find yourself drawn to something, a talent, a passion, don't be surprised that it's choosing you. Just go for it!