How did Sophie's life change after her father's marriage to Araminta in the novel, An Offer from a Gentleman?

Until she was ten, Sophie was treated like the daughter of an earl.... which she was. When Araminta arrived, however, she confronted Sophie in the nursery to tell her that she was inferior to her and her daughters because she was illegitimate. After her father's death, Araminta forced Sophie to be a servant in her own home.