About 1 1/2 years into HRT. I began transitioning late in life but have made up for it!
I was shopping in a large Department Store in NYC (Century 21) and was in the women's clothing section. I needed to pee and I saw a store clerk so I asked her "excuse me, where is the nearest restroom?". I left out "women's" and wasn't sure to use "men's" since I wasn't sure how passable I was as a gal. She pointed to the women's restroom and I immediately froze at the thought that I would be using a public women's restroom for the first time. Before I could make an excuse like, "ok, I'll use it later"....the clerk responded, "here honey, why don't you give me the items you have and I'll hold on to them while you use the restroom."
At this point, there was no turning back. It felt like an out-of-body experience as I made my way to the restroom. I mentally prepared myself for screams of "it's a man....call the manager". So avoided all eye contact as I entered the bathroom. Out of my peripheral vision I saw 2 women talking by the sink washing their hands. I saw an empty stall (the one next to it was being used). I literally ran to get inside the stall as I was still expecting a negative reaction. I, of course made sure to squat to pee. I was hoping for the women to be done so I can wash my hands in the sink but they were still there and gabbing (tourists), so I summoned courage to go to the sink. I avoid all eye contact and much to my surprise, no one noticed or said anything.
I thought this was pure chance but a few weeks later, I was shopping in a Whole Foods and needed to use the restroom. There was a store clerk adjusting her apron. The men's room was on the left and the women's on the right. I made a beeline for the men's restroom. Before I could open the door, the store clerk said, "no it's this door" and giggled, pointing to the women's bathroom. Ever since those experiences, I use a women's public restroom all the time - airports, restaurants, cafes, public spaces, etc.
Although I begin transitioning late, it does help that I am 5'4".