Hang on.

Let W = "The Forces of Good will win an epic battle against the Forces of Evil." Let C = "You will be instrumental in winning an epic battle against the Forces of Evil." Let B = "There will be an epic battle between the Forces of Good and the Forces of Evil."

What "You are the Chosen One" usually means in Western fiction is:

B is true, and; W if and only if C.

Thus, if you are definitely the Chosen One, and you stay home and read magazines, and reading magazines doesn't help you win epic battles, and epic battles are relatively evenly-matched, then you should expect to observe (B ^ !C ^ !W), i.e., you lose an epic battle on behalf of the Forces of Good.

Fate can compel you to the arena, but it can't make you win.