This Book is a Time Machine

Hello there! Guess what? You are holding a real-life time machine!
You don't believe me? I'll show you!
For a start, I wrote this blurb in the PAST.
Yet, you are reading it in the PRESENT.
And when you finish reading the blurb, it will be the FUTURE.

Tell them the bit about what happened when the past, present and future collided! - Lucinda
Shhh! The blurb isn't meant to give away the whole story! - Tracey
But that's the best part! - Lucinda
You reckon? - Tracey
Why don't you let them decide? - Luci...