"Destiny... is the power that controls what happens" Really, is she nice?
"But you can change your future by what you think" So, destiny has no power? Or are you saying that we make our own destiny?
I think you're oversimplifying things. We have power over our own choices, sometimes we don't even have that (when we're in pain, fear, anger, intoxication, deceived/misinformed or otherwise incapacitated) and we don't have power over the world at all. The only thing we can say for certain - which you may call "destiny" is Hebrews 9:27 "And as it is appointed unto men once to die, but after this the judgment".