You would still have the same age, gender, personality, skin color, etc. and you would be able to speak at least one local language and would know basic information of the era and place. Your family, social standing, and such would be randomly picked.
1940, as there are crazy things that will be going on in the world of computer science (and science in general) over the course of the next few decades and that would be really cool to experience. Kind of sad though to not be alive once we achieve human-level artificial intelligence, would be interested in seeing how that will turn out. I would probably chose America, as I wouldn’t want to spend WW2 in Germany where I live in the present.
Alternatively I think I would very much enjoy visiting Ancient Greek, although I’m not too sure when would be the best time for that; maybe at the peak of Athen.