Sherri caught her without thinking, mind still trying to catch up. "Oh my God, Joss! I'm... what are you doing here? Do mom and dad know where you are?" There was no way they'd approve. Then again, they probably approved of her even less, at the moment, since she knew they had no idea where she was.
Before they could even get into that conversation, she tried a quick derail. "You look so good! What have you been up to?"
She would explain everything to her little sister eventually. The sidewalk, however, just wasn't the place.