Agatha would have been very close to terrified. She would have stayed very firmly by her father's side and kept her eyes on the floor or her clasped hands when she was sitting down. She have been silent and sober through out though she would have done her best to smile and pretend to be happy during the rousing speech.
Both before and after the meeting her father would have done a lot of schmoozing and brown-nosing with as many of the DEs as he could with Agatha at his side so feel free to have your characers be annoyed/amused/indifferent to that if you like. If you don't then Charles just never got around to approaching them. *grins*