Hicks grew up in Oxfordshire, England. She spent holidays at the family estate in Ireland and at her father's self-designed and built Bahamian-holiday home. As a child, she was a tomboy who kept her distance from royal affairs. Hicks was exposed to design at an early age through her father and brother, who were both architects. The 11-year-old Hicks was on vacation in Ireland in 1979 when her grandfather was killed by a bomb planted on his boat. In 1981, she served as bridesmaid to Lady Diana Spencer at her wedding to Prince Charles.