It's discussing a marriage. Vdaná is an adjective and means "married". (The male version is zenatý.) I think, the English translation is correct - It means that the woman, at an earlier point, was not yet in a marriage, so not married yet. "You have not married yet." or "You didn't get married yet." is in Czech "Jeste ses nevdala." Is it clearer? (Sorry, I have no Czech letters on my keyboard.)
As a native UK English speaker, "You were not married yet" is just wrong. "You are not yet married," or "You were not yet married," would be better. Optionally and widely acceptable colloquial English would be "You are not married yet," but leaves a hanging preposition. A better colloquial form would be "You weren't yet married."