What you choose to do now doesn't have to be what you'll do for the rest of your life. If it doesn't work out, you can change course later.
So, just start. Explore your interests.
You don't need a detailed plan. A lot if it will unfold as you move forward. But you do need a figure-it-out mentality. Because there will always be surprises, and you've got to figure out how to move forward in times of uncertainty.
Just start something. It may or may not be what you end up doing, but try your hardest to make it work.