How am I suppose to decide on an education that will shape my future?

I am only eighteen years old and at the beginning stages of my life. I have finally reached the college level and it is now time to settle down and figure out what it is I am meant to do in life.

So I ask: What is my purpose? What will I be good at? What will make me happy?

I do not want to pick a job in which I am unsatisfied later down the road and so I need to decide what I want to major in so that I can figure out what classes I am suppose to make.

How do I discover that thing? That thing that I am suppose to do when I’m older. My future is coming closure and I do not want to be left in the dust. How do I find what is good for me?