Where I grew up in the US, in grade school, our neighborhood school in the small city had teachers from both Quebec and Ireland. So we learned non-US spelling first. That caused a pain when I and my friends ended up in high school and had to use US spelling.
But to me, who cares, there was a time ages ago people spelt a word the way they wanted and no one cared. Just look at old documents from the 18th century in the US.
Even decades later, once in a great while, I end up using colour instead of color :)
I never grew up in a British family, or had any sort of close proximity to British things. But I still somehow ended up using "grey", "colour", and "behaviour". They just look more correct.
But to me, who cares, there was a time ages ago people spelt a word the way they wanted and no one cared. Just look at old documents from the 18th century in the US.
Even decades later, once in a great while, I end up using colour instead of color :)