Prima-donna

A very temperamental person with an inflated view of their own talent or importance.

"the prima-donna behaviour of some of the stars"

Prima Donna

Basically what Isabella Madrigal used to act like.

Look, it's Mister Mariano, hey
You can marry my sister if you wanna but (Mirabel)
Between you and me, she's kind of a prima donna
Yo, I've said too much and thank you but I really gotta go (Mirabel)