I could not find information about her.
From the Google Art Project via Pinterest.
Mary Wither choses not to be portrayed in hurluberlu style, wearing a complex and elegant curly coiffure instead.
Keywords: Beale, Mary Wither, British, curly coiffure, jeweled headdress, earrings, necklace, chemise, off shoulder scoop neckline, under-sleeves, wrap, bodice, jeweled bodice ornament, puffed over-sleeves, clasps