After carrying out her graduate studies at New York University (NYU), she started teaching in the Cayey campus of the University of Puerto Rico where in 1986, she founded the Project for Studies of Women.
Ostolaza teaches at the University of Puerto Rico Río Piedras campus.
A former member of the Puerto Rican Independence Party (PIP), professor Ostolaza was elected Senator from the district of San Juan in the 2000 elections as a candidate of the Popular Democratic Party (PDP).
[2] In 2004, she was unsuccessful in her reelection bid, when she and her running mate, Sen. José Ortiz Dalliot were succeeded by the candidates of the PNP Roberto Arango and Carlos Díaz.
[3] In 2008, Ostolaza ran again, this time for Senator at-large, in the PPD's March 2008 primaries, appearing in the ballot's No.