“Oooh ooooh ohhh
We're bigger than we ever dreamed, and I'm in love with being queen”

Lorde – Royals Lyrics on LyricsMode
EXPLANATION
She means that to just trust yourself, and don't believe in your dreams. Because, you are bigger that your dreams.
EXPLANATION
She means she is famous and a big person to other people, she been dreaming for this.
EXPLANATION
Shes saying that they are bigger and better than anything they couldve dreamed of.