At the highest level the lines and the steps of destiny are all determined. However at the level where we operate it is better to take it as a consequence of the choices we make. We can say that there is a relative freedom given to each thinking creature to choose his path but whatever be the path he chooses, he cannot go beyond the ultimate truth of his being and the eventual destiny fixed for him.
It is somewhat like a role given to each actor in a vast cosmic play in the theatre of life with ever changing scenes. We can play the role well or play it badly, we may need lot of learning and practise or less, yet the successive roles and the scenes and sequences are fixed. In simple words, human will has been deliberately left free though only to a certain extent and our choices do matter. That is the whole basis of the law of karma.
Affectionately,
Alok Da