why did jo seemed to be careless at the party of mr. gardiner?

Jo is trying to hide a lemonade stain on her dress which makes her look a little awkward. Jo also feels clumsy because, once sanding too close to a fire, she burned her frock. Joe agrees to keep her back to the wall during the party so not to embarrass her sisters. There behind the curtains she meets Laurie. Jo also admits to Laurie that she is rather careless when she dances, "In a place like this I'm sure to upset something, tread on people's toes, or do something dreadful, so I keep out of mischief and let Meg sail about..." Ironically it is Meg that turns her ankle at the party.