The Struggle with Gendered Binaries

I volunteer at an LGBTQ resource center and one of the things that's emphasized is the use of non-binary gender pronouns (or just not using pronouns at all). The other day a transwoman who had not yet transitioned came up to the desk to check in for an appointment. A coworker called back to the department where the appointment was and told the person on the other line that he would send "her" back to the waiting area. The client quickly corrected him, and he apologized. I was indignant--it was clear that the client was in the process of transitioning. My righteous indignation was quelled somewhat when I used a gendered pronoun myself later in the day to describe another client.