Why does Mrs Bennet say Lydia my love though you are the youngest i dare say mr bingley will dance with you at the next ball in Jane Austen's Pride and Prejudice?

Actually, the quote is "Lydia my love though you are the youngest, I dare say Mr. Bingley will dance with you at the next ball". Mrs. Bennet says this because Lydia is her favorite child, her mother believes she is good-tempered and bold.