Is fate predetermined or is it based upon your choice?

Is your life predetermined your life already decided like a character in a book or is there free will. If fate does exist then are there really criminals because they can't change their fate so should they be blamed for their actions. Then again if fate doesn't exist and its free will then how do we know, because it might by fate that we are thinking that fate doesn't exist. Is this a paradox or is it possible to determine.