In chapter 7, Mattie's mother is quite anxious about having tea at the Ogilvie mansion for a couple of reasons.
First of all, the Ogilvies are extremely wealthy and belong to the upper crust of Philadelphia society. This is made quite apparent upon their arrival at the estate. The Ogilvie daughters are dressed in expensive matching outfits and are learning French from their own private tutor. They talk about their connection to the Washington family and that Colette Ogilvie is engaged to the son of Lord Gathering. Mattie and her mother are rather out of place in such a setting.
The true reason for Mattie's mother's anxiety and eagerness is shown when she asks about Mrs. Ogilvie's sons. It becomes clear from her repeated questions that she would like Mattie to marry one of the Ogilvie boys. Of course, this would be marrying down for an Ogilvie, and the conversation goes nowhere. In fact, it ends with a verbal fight between Mattie and one of the Ogilvie girls.