Some idiotic producer out there is thinking, Wow! She actually sang without the help of an auto-tuner!!
This is a really good performance, a fantastic buildup and a tremendous bit of singing. Nothing will ever beat the true power of American show business.
I can attest that you can be nervous when you go out on stage, but when you start performing what you’ve rehearsed (and rehearsed and rehearsed, etc.), well, that just takes over and there you are.
It was totally an act. Look her up. She’s appeared on a couple (and made the finals on one) of different talent contests in England. You could tell right when she moved back to “her spot” to get into her dance position. Most singers sing from where they are talking to the judges. Her audition and dance moves were very well rehearsed