It’s probably because when she over heard the mean girls talking it got in her head and she thinks that the prince is using her by asking her to dance.
Plus this would actually push the prince to wanna tell her how he feels and why he couldn’t break things off with lady irene because of the threat.
So you just refused to dance.. THEN ACCEPTED someones offer?! Like bruh! You know he WILL see you right????
I mean yes you can dance to whoever you please, but you just LIED, if you're going to lie atleast stand to your statement...