This is a very important question, that we all should consider, because the implications would change the nature of humanity. If we do not have free will, then could any of us truly be held responsible for our actions? However if free will is truly ours, this means that we have the ability to change any outcome, now and in the future.
The following, strange read, explains why in a quantum sense we must have free will. So choose to read this or not, it is up to you!
Robert Nozick....why there is something rather than nothing, quipped: “Someone who proposes a non-strange answer shows he didn’t understand the question.”
Science experiments always presume complete freedom of will; without it, how would we know that some grand conspiracy isn’t manipulating our choices to hide the truth from us?
I see no contradiction whatsoever between determinism and free will, because they operate at two different levels of reality. Determinism describes the basic laws of physics. Free will describes the behavior of conscious beings. It is an emergent property. Individual particles aren't free. Nor are they hot, or wet, or alive. Those properties arise from particles’ collective behaviour.
After all, physics is reversible. What determinism means is that the state at one time implies the state at all other times. It does not privilege one state over another. Thus your decision, in a very real sense, creates the initial conditions of the universe.