To play devil's advocate, many people that are born in less than ideal circumstances have to work harder to get to certain privileged positions than others. I don't know your gf's background but if she was the typical kid that went to my high school (low income, latino, first generation, high risk youth) then yes, it's great for them to beat all odds and become a doctor. It's much easier for a kid born to a well off American family to become a doctor.

Maybe your ex gf was from a well off family and Mexico; if that's the case, then I wouldn't be so surprised. People use ethnicity as a yard stick for minority struggles, which is not correct at all. But as a first gen latino myself, this is something I've caught myself thinking as well because I know how hard it can be to pursue med school, especially for people knew to the country and from lower socioeconomic status.