Thomasina was elected in 2018, currently serving as Charles County Commissioner, representing District 2.
Thomasina is a member of and serves on several local and regional boards across the Southern Maryland region: The Waldorf Business Association, Chairwoman of the Southern Maryland Tri-County Community Action Committee Board of Directors, and Vice Chair of the Tri-County Council Executive Board. She serves on the Area Council on Aging, and College of Southern Maryland Unity Community Diversity Forum Planning Committee and Mediation Committee. She also serves on the South Potomac COMREL, Commuter Ferry Stakeholders Group, Metropolitan Washington Council of Governments (COG), MACO Tax subcommittee and Charles County Homeless & Emergency Shelter Committee.