Start Doing Something
It's hard to know what you want to be doing the rest of your life. Maybe you're really good at one thing and the choice is easy. But maybe you have talents in multiple, very different areas. Then it becomes more difficult.
When your desires and skills vary widely it can be hard to get started. Being a jack-of-all trades can also wear on your confidence. You start questioning if maybe you need to get a degree in some area before you pursue a dream.
Know that no matter your education, qualifications or reputation, any new endeavor will meet opposition (including your own self-doubt). Don't wait for anything, start today. If you want to be a writer, write something. Even if it's private and no one else sees: do it. If you want to paint, go get a brush. You want to be a runner, go jog around the neighborhood.
You won't release an album, publish a novel, or go to the Olympics anytime soon, but that's ok. Choose one path, one skill, one talent, and do something with it. Today.