She left home at the age of fifteen to fight in Nicaragua with the Sandinistas to overthrow Anastasio Somoza.
When she returned she joined the People's Vanguard Party and studied graphic design at the National Learning Institute (INA).
Muñoz is characterized by her support for Feminism and the fight for equality for the LGBTIQ community, as well as promoting recognition of same-sex unions.
In May 2013 the congressman and evangelic minister Justo Orozco of the Christian Costa Rican Renewal proposed a motion to exclude Muñoz from the legislative commission that was going to analyse the law project to legalize the unions of same-sex couples, due to what he saw as a conflict of interest.
The following day the Legislature gave Muñoz an ovation for her work as a congresswoman and she received flowers from congressmen on both the right and left.