She is sick of it. Sick of the cycle her life has become. Twilight Sparkle is sick and tired or the repetition of her life, making new friends then having to watch them grow old and die before starting the whole cycle again. She wants to rid herself of the immortality of being an alicorn and live out the rest of her life as a simple unicorn.

She finds a way to do it, and is willing to take it no matter how scandalous it may be…

——-
That's to Mr101 for pre-reading.