Sheelagh Warren was Headmistress of Gayaza High School for 18 years. She took over from Miss Joan Cox when she left, having overseen the development of the secondary school to O' and A' levels, the construction of most of the permanent buildings and the establishment of the school's reputation for academic excellence, and more. Warren steered the school through Uganda's most turbulent times - through the 1979 war that toppled Idi Amin, the five-year National Resistance Army guerrilla war that brought NRM into power in 1986. Despite the insecurity and scarcity of the times, the school continued to run successfully. Ms. Warren turned 90 in November 2017 and the "Warren Computer Center/Laboratory" at Gayaza is named after her.