Who is Cassandra Miles-Porter from Memoirs of a Teenage Amnesiac and what is their importance?

Cassandra Miles-Porter is Naomi's adopted mother. Cassandra is half-Scottish and half-Japanese. She is originally from California, but met Naomi's dad when they were in college in New York City. Before Naomi's parents' divorce, Cassandra wrote wine books with her husband, who was responsible for taking the pictures for the books. Four years prior to Naomi's accident, Cassandra and Naomi's father got a divorce because Cassandra had an affair with her high school boyfriend and got pregnant. Naomi has been estranged from her mother since the divorce.