But I thought gender was a fluid. How are we supposed to keep up?
If someone tells you what gender they identify as, address them according to that gender. I don't believe it makes any sense for me to go around asking what pronouns people prefer - it could make someone uncomfortable, make them think I'm accusing them of being something they're not, or just plain look stupid. If you don't tell me anything, I'll just assume based on appearance/prior statements. But if you tell me you're transgender/non-binary/what have you, I'm going to be decent and respect that. Because transgender people exist and are a fact of life.