About the Christians around me: it is not explicitly considered rude, but it is a signal that you want to challenge their worldview, and if you are going to predictably ask that kind of question often, you won’t be welcome in open discussions. (You could do it once or twice for anecdotal evidence, but if you actually want to know whether many Christians believe in a literal snake, you’ll have to do a survey.)
About the Christians around me: it is not explicitly considered rude, but it is a signal that you want to challenge their worldview, and if you are going to predictably ask that kind of question often, you won’t be welcome in open discussions.
(You could do it once or twice for anecdotal evidence, but if you actually want to know whether many Christians believe in a literal snake, you’ll have to do a survey.)