My pronouns are He/Him/His. I absolutely get tripped up on They/Them/Their. The good news is, in the instances were I was corrected--it was polite and not awkward.
I am all for people living their truth and being comfortable in their skin. That being said--it can be confusing. Hopefully, the person is understanding, gives grace and is patient. It's still fairly new. Not everyone is going to grasp it, remember it, or even like it.
Your intent is one thing but your IMPACT matters more. If you make a misstep, own it. Apologize. Learn from it. On a call last week, the agent told me up front that his pronouns are they/them/their. After I slipped once and they politely corrected me--I wrote the pronouns down on a post it note and placed it right in front of me.