Who is Celia Lacey from The Favored Child and what is their importance?

Celia Lacey is the woman who raised Julia as her own and served also as a surrogate mother to Richard. She was a wealthy young woman. Her own mother and stepfather live nearby, providing at least some comforts. Celia is every bit the gentle lady and feels that she has failed in trying to keep Julia an "indoor girl." Celia is most at home in Bath, among the people of society, though she never complains of the hardships her simple country life have brought.