I was hard on myself during my time as Princess Twilight's student. Nothing but my studies had mattered ever since she saved me from my own magic. When I finally burned out, Equestria was on fire.
When a daddy Unicorn and a mommy Alicorn get together and love each other very much, they get a rambunctious little Flurry Heart. When a daddy Siren and a mommy Windigo get together and love each other very much they get...a very lonely creature.
She was sent away from her kingdom when she was young, so she wouldn't be taken prisoner again by King Sombra. She grew up away from the empire. Now, she's the one who has to save it. First from Sombra, then from Chrysalis.