We spend a lot of time thinking we should know what's next.
My experience is that we do not know, and that we rarely will. We may be hoping that a mission statement will drop down from the sky, or that there will be a burning bush that talks to us. Most of us would settle for a booming (or even not-so-booming) voice in our heads!
Have you ever flipped a coin to make a decision, or asked for a sign? Then you know what I am talking about.
Stop waiting, and do what you want to do. Do what you feel passionate about, without fear of mistakes (or more realistically, despite that fear). It's a lot easier to course correct than it is to start. So start, and the rest will follow.