I don't recall talking about culture very much growing up - my family is German, Scotch-Irish (I think) - except maybe when we lived in Europe and traveled in a few neighboring countries when my dad was on leave. Mainly, I remain more influenced by my father's military career and the changes brought on by moving to a new place every few years. In high school, I remember an argument I had with a black friend over being American vs. African-American - in my world, if you were born in the United States, you were an American regardless of what ethnic background/s your family was part of - we ended up having to agree to disagree about it.
I have been guilty of asking some of the microaggressive questions - sometimes, I'll ask about ethnic background more than "where are you from?" due to the inner conversation I have when I'm asked where I'm from - nowhere and everywhere at the same time. There were other things I had been unaware of - that Natives/Indigenous folks have to prove their heritage via blood count - it also reminded me that it could go in the opposite direction for some mixed race folks where even a tiny amount of certain ethnic backgrounds meant you were that particular background.
It is only in recent years that I've really given my European-descent heritage much thought at all - I am constantly surrounded by media and other images that sustain the idea that whiteness is normal. I don't consider myself color-blind, though I'm not skilled in determining some ethnic backgrounds without being told.