<p>UK and american english differ slightly, I personally don’t think that makes a lot of differences and as long as u don’t write color and after that colour, u will be fine.</p>
<p>use whichever. it doesnt matter.</p>
<p>i have the same problem. honestly i would just use american english as i dont think an average american high school teacher has any understanding of these sorts of nuances.</p>
<p>Even people with high amounts of education in English might not realise all the differences in spelling. Honor vs honour is common, but less so things like defense vs defence. There are also grammatical differences: it is incorrect in American English to put a period outside of quotation marks, but correct in British English. </p>
<p>As far as knowing both, it is not altogether difficult and doesn’t require living abroad. I have lived in America my entire life and use the British version of English MUCH more naturally than the American, because that is where most of my reading comes from.</p>