Bro this is so relatable it has happened to me a few times as well. Im from Guatemala and my native language is spanish, but I recall like 4 or 5 times where I was speaking for the first time with random people and the first thing they asked was "¿Are you from another country?", then I answered them "No, why" and then they were like "I thought you were from another country due to your accent... I know they dont have the intention of being rude by asking that question but I find it kind of annoying. But at the end of the day, I dont blame, perphaps they are just curious and really think im from another country. I just wanted to share my experience too.