Generally, people are pretty chill about it. If you are unsure how to refer to someone, you can always just call them by their first name or something else (the barista at the front counter, the person in the yellow sweater, etc!)
I wouldn’t overthink it, most people are totally cool if you get it wrong, especially if you show a willingness to get it right from then on. Queer people just wanna be treated like everyone else :)