Ok, so I've gotten a couple of comments on this. This is my take.
I believe fate and destiny, while related, are different. To me, fate is unnavoidable. If you believe in fate or that you are fated to do something, nothing you can do, no choice you make, will change that. It will happen. You are fated to it.
Destiny, on the other hand, is what you are meant to do and that there are paths you can follow that will take you to your destiny, but there is no promise that you will meet it. I think if you listen to yourself and are just aware you know if you are on the right path to whatever your destiny may be. I also believe that you know damn well when you aren't on the right path, even if you choose not to listen.
Now neither of these talk to how your fate or destiny is set and that is a different subject all together.
I don't believe in fate but I do believe in destiny. To me, fate, as I defined it above, is just the easy way to avoid responsibility for your decisions and actions.