Jenny Simpson would have been a better answer to the hero question, but I can understand a 17 year old kid saying Mary Decker.
When Decker won world double gold in '83, she was my hero too (even though she once tried to kill me with the EVIL EYE when I was running intervals at South Eugene High in '81; she was there with Ron Tabb for a photo session, sort of "go away you nobody, for I am here!".)
I don't dig the cheap shots at Pre on this thread. Go read Kenny Moore's "Men of Oregon" and get your facts straight about Pre's death. He was no saint, but he was a great runner and yes, he was, and still is, a huge hero to me.
To American runners coming of age in the early/mid 70s, Pre was a thrilling inspiration and nothing can ever change that.