Zanna is too old for playdates. She has explained this to her mother at length. As usual, her points were ignored.
Also, this boy is, by all accounts, boring. She's been told this by everyone who's met him. (She doesn't really take into account that they're boring too. If anything, wouldn't they be the best positioned to know?)
She doesn't want to go. But she knows if she drags her feet too much, Mom will be insufferable. So she just gets in the car and tolerates the chatter until they come to the little house where her new playmate resides.