I've been to some of the tapings.
And let me just tell you, I was very dissapointed in Britney, she's so boring and barely says anything. She repeats the same exact words as Demi during critiques.
Demi is definitly mature for her age and not to young. She was the best judge tbh, very honest and not easily swayed.
Simon and Demi's bickering is whats gonna keep the show going, its very cute.
Her face at 0:24 when someone shouts "Demi, why are you so sexy?"
maybe it will be a surprise performance hopefully 
, if she peaks in #11 tho