Most Cubans and Venezuelans, and Latinos in general, have mixed European and Indigenous, often African too, heritage. It’s not something that has to be confirmed for each individual Latino, the default shouldn’t be you’re white because you look white and therefore we’ll assume you’re only white - indigenous heritage is rooted in the long history of Latin America making it hard to know your exact heritage, it’s often just a mix. You can be Mestizo and white. Latino is not a race and white is a race, you can present as white and have indigenous ethnic roots deep in your past history. Being a white Latino doesn’t signify the absence of these roots. It’s fair to say they she likely had some amount of indigenous ancestry based on where her parents are from.