What do you think Rowling is saying about fate and destiny in the Potter books?

I don't really know if she's saying anything about destiny or fate. I think her point was that everyone makes their own choices, and those choices have their consequences. Cause it wasn't Harry's "destiny" to become the one who killed Voldemort. Dumbledore tells him that he could decide wether or not he was going to be or not. Harry was basing everything on the prophecy, but Dumbledore told him he could choose. And Harry choose to follow it, which then lead to the prophecy coming true. If Harry hadn't, well, the prophecy would be wrong.