I'm 50 and live in Oklahoma City. I've spent a lot of time in Dallas, though. Now, I remember people my age using the word "dude" in my college days. But it seems as silly an affectation to me today as it did then. I simply don't use the word. But if I did (which I don't) I'd still be far less likely to call a female "dude" than I would a male. And in fact, in Internet forums, I note that "dude" is used as a form of address between males far more often than between males and females. And when it is used in that respect, it would most often be the female addressing the male as "dude".
I tend not to participate in groups where the term is commonly used, for other reasons. People I find interesting simply happen not to use the word.