Under The Mistletoe - An MLP AU

Meet Aurelia Breeze, she's the secret daughter of Celestia. She's an alicorn princess, she's immortal, she gets to become queen one day, you cant get anything better, right?
Until a certain young unicorn excels in her entrance exam to Celestia's academy. Then everything changes.
Celestia dedicated her time to educating the unicorn, Twilight Sparkle in magic and its properties. Aurelia never sees her and spends most of her time locked in her study, trying to find her flaws in magic and trying to become better than the unicorn.

One day, she comes across a spell to change the universe, create alternate realities, but its risky, possibly erasing some ponies' existence. She forms a plan to destroy her current reality and create a new one. Then Aurelia spends years trying to master the spell, and in that time, the unicorn becomes an alicorn. This infuriates her, although she has just mastered the spell...

Will Aurelia finally become queen? Or will the spell erase her own existence?

( This is just an AU if Twilight didn't exist- )
( Yes the title comes into it at some point- )