It is 6 billion years older than Earth and 1.5 billion years older than our Sun. So maybe we're Earth 2.0 or Kepler-452b 2.0
This is incorrect. I got confused too when reading it. Kepler 454b's host star is 1.5bn older than the sun, not Kepler 452b it self. The planet, Kepler 452b is more than 6bn years old.