How could I know if I am living an amazing life?
Do you mean how can you tell if you’re living a life that other people consider amazing? Easy. By reading accounts of amazing lives (biographies, obituaries, etc) and comparing them to your life.
How can you tell if you’re leading an life that you consider amazing? Easy. If you’re often amazed by what happens to you, you are. Otherwise, you aren’t.
Marcus Geduld on this Quora post.