She graduated as a registered nurse from Baptist Memorial Hospital System School of Nursing (now Baptist Health System) in San Antonio in 1984.
She is allied with the Ron Paul and Tea Party movements. Medina ran unsuccessfully for the Republican nomination for Texas Comptroller of Public Accounts in the primary election held on March 4, 2014. The position is being vacated by the two-term incumbent, Susan Combs.
In 2010, Medina ran in the Texas gubernatorial election.
She participated in the January 14, 2010 televised debate with incumbent Governor Rick Perry and challenger United States. Senator Kay Bailey Hutchison. After subsequently tripling her support in public opinion polls, she was invited to participate alongside her two opponents in a second debate held on January 29.
She earned her business degree in 1995 from LeTourneau University in Longview, Texas. In 2002 she founded and managed Prudentia Incorporated., a medical billing company based in Wharton in southeastern Texas.
She was reared Roman Catholic but now attends a Baptist church.
She was a high-level volunteer for Ron Paul’s 2008 presidential campaign, and served as Interim State Coordinator for the Campaign for Liberty. At the 2008 Republican Party of Texas state convention in Houston, she lost her bid for state Grand Old Party vice chairwoman. In 2008, she decided to run for governor.
The case was originally dismissed on an issue of jurisdiction, but the party demanded $14,000 for attorney fees.
Medina appealed the case to the 1st Court of Appeals. In December 2009, Medina filed on the Republican ballot for the 2010 Texas gubernatorial race.
In the Republican primary on March 2, 2010, Medina finished with 18.6% of the vote, behind Perry (511%) and Hutchison (303%). In an interview on the Glenn Beck Program on February 11, 2010, host Glenn Beck asked Medina if she thought the United States government might have had a role in the 9/11 terrorist attacks.
Medina said that "some very good questions have been raised in that regard.. the American people have not seen all of the evidence there, so I have not taken a position on that." Soon after the interview her campaign released a press statement disavowing any 9/11 conspiracy beliefs.
Medina finished third in the 2014 comptroller"s race with 235,713 votes (193 percent). The leading votegetter, State Senator Glenn Hegar of Katy, polled 610,512 (4999 percent). State Representative Harvey Hilderbran of Kerrville finished second with 317,731 votes (26 percent).
Former State Representative Raul Torres of Corpus Christi ran fourth with 57,255 votes (47 percent).
On March 7, 2014, Hilderbran announced that he was ending his campaign and endorsed Hegar as the Republican nominee in the fall.
Medina got involved in politics in the 1990s and became Wharton County Grand Old Party chairwoman in 2004. Prior to the 2008 Republican Party of Texas state convention, Medina sued the party to ensure that the convention would be held in accordance with the Texas Election Code.