If you're not sure you want to do just one thing for the rest of your life, you're not alone. Career coach Emilie Wapnick describes multipotentialities as those of us with many interests, many jobs over a lifetime, and many interlocking potentials. She actually wrote the whole book about it: "How to Be Everything."
It's funny in the way our society wants to peg us for certain job by the age of 5, and then again 13, and 18. We do this subtly when we start asking our kids who they want to be when they grow up, as soon as they start talking. I remember asking my 4 year old that same question(seems like very long time ago, he is 10 now), and you know what his answer was? "I want to be a daddy when I grow up." But what happens when you are the multipotentialite? And you have many dream jobs, and many aspirations?
I think the bottom line is, don't be scared you are not alone, think big and make sure you are not stuck for life with one job, which drains your energy because you were meant to be many things.
References: "HOW TO BE EVERYTHING" A Guide for Those Who (Still)Don't Know What They Want to Be When They Grow Up" http://howtobeeverything.com/