This isn't an annoying question and I don't think it will ever be to be honest. This is a relieving question, and the answer is simply to ask in a polite manner such as,

"Excuse me Name, what pronouns do you use?"

It's that simple, and it goes a very long way! It shows that you intend to lend respect from the get go, not have it pulled out of you. Thank you very much for the question!