Twilight Sparkle thinks she will never die.

She wasn't prepared when her friends died, when she could only die when her domain - friendship - faded away. Friendship never faded. She was stuck being immortal for all of time. Even dragons - even Spike - were not fully immortal like she was, just long-lived. Even Celestia and Luna went, when the sun exploded and obliterated the moon. Even Discord went, when Faust, the Creator, fulfilled her promise and remade the world into perfection. Yet she was stuck as an alicorn, watching universes rise and fall.

Twilight Sparkle is wrong.