Nothing about you, including your personality, was ever predetermined. We are all born exactly the same. As blank canvases.
And our subjective experiences tip buckets of paint onto our blank canvases. These random spills of paint color us with personality and thought. The random spills create us.
But of course, with randomness you have no choice as to what paint you want on your canvas. You have no control in regards to what your experiences say you are supposed to be, or how you are supposed to act.
That is, unless you reach a high enough awareness level to realize that you had a paint brush this whole time. And that you could have given form to the said paint that was freshly splattered onto your canvas.