Princess Celestia had known Twilight Sparkle for a long time, same goes to Sunset Shimmer. But when it comes to the Mirror World, they’re is little she knows due to more things her former student has come across. This moment eventually needed more time then necessary but at the end of the day, Twilight has somepony to show her idol that will change her life forever.

Thanks to Daniyel099 for editing this.
https://www.fimfiction.net/user/292246/Daniyel099