Yeah I didn't think the performance was all that memorable and it was just ok for me but she didn't sound bad by any means. The audience really didn't seem that thrilled which I thought was odd.. but I'm not judging her too much as it was her first major performance of the song. Gotta work them kinks out.
It could've been much better, there are 3 different videos of her performing Good Girl , and in all of them she sounded better then here.
But, she was obviously very nervous here... and I'm sure the breathing issues will be over once she performs it more, same happend with Cowboy Casanova
She just has to work a bit on the live rendition of the song, but at least she sang live as always