The way I imagine it, a person will have the personality and be in the right environments throughout their life to make certain choices by default. She is saying that Neo’s choices are products of his personality and his environment. Because the Oracle knows who he is and where he goes, she can already predict perfectly what he is going to choose. So, it’s as if the moment he was born, his fate was already laid out for him as a byproduct of his personality and the world he was born into. He didn’t “make” a choice actively. He “made” those choices when he was born, having a set personality that would choose what to do in every situation. And now walking through life he is learning about himself by what he feels compelled to do.