Kirby is from Orlando, Florida. She earned her undergraduate degree from Duke University, where she designed her own major in Global Health. During her undergraduate career she worked extensively on initiatives to increase global access to medicines, with positions at the World Health Organization in Geneva, the Duke Program on Global Health and Technology Access, and research projects on India's AIDS drug industry. She has also been involved in social justice issues in her local community, serving as co-President of Duke's Center for Race Relations and working to extend legal protections to farmworker women in the Carolinas. As an accomplished artist, Kirby runs a portrait painting business and has used her talents in art and documentary to raise funding and support for girls' educational opportunities in rural Kenya.