It took me several years to realise nobody could tell. I was always waiting for it; fearing the moment when it would turn out I'd just been being humoured; that secretly people were just being polite.
Once you realise clinicians are assuming you are here to attend maternity departments and people are behaving in ways that demonstrate they have psychologically categorised you as 'cis female' even in the presence of trans women they are subconsciously behaving differently around, you realise that it's actually kind of ridiculous to keep your walls up.
When I saw that one of my older cis female friends was occasionally getting accidentally misgendered even when I was literally stood there right next to her, and saw other trans women being regularly misgendered even while once again standing right next to me, I realised that people really can't always tell and as long as I was careful about what I said, I'd be safe.
The first time I disclosed after nearly a decade of complete and repeatedly demonstrable invisibility, I did so exclusively to a group of other (misogyny-subject) feminists I had spent years carefully scrutinising and slowly learning to trust. They had no idea and some initially thought I was joking because it was so out of nowhere. There was a lot of 'You didn't need to tell me and I'm kind of sad that you were scared, but thankyou for sharing. Also...I know trans people and had absolutely no idea that was even possible, what the hell?'. I did ask if there was any advice and offered to remove myself if it was a problem for anyone and got a unanimous 'don't you fucking dare imply you have any less right to be here than any of us' scolding which rather set the tone for the future.
It could have just been a fluke that time, but the same has happened again and again for years and years and the general baseline of society has moved in a positive direction.
Around 2017 the evangelical right's pivot toward using trans people as a wedge issue caused it to start becoming more dangerous to be visibly trans again. Trumpism manifested as a neoreactionary extinction burst, the papers went full mask-off over here and it wasn't long before suddenly the transphobic FPFW flyers started mysteriously appearing all over publicly accessible safe spaces, even in academic institutions with positive cultures of tolerance.
Trans people were being more generally accepted as a baseline, but were also seeing more active abuse from highly radicalised anti-trans activists. Some of my friends - sometimes even cis women - would get challenged. It was terrifying.
Weirdly, though, they never once targeted me. I've walked right through groups of anti-trans activists hurling abuse at any visible trans people they see over the last few years; I even had to stop and ask them to please get out of the way so I could get to my train once. Nothing.
When I heard a cis woman being hasseled by the same group later in the day for being tall and having short hair I began to realise what was actually going on and where things were going - the pretence is slowly falling away as the overton window shifts and the quiet part starts becoming audible.
The phenomenon of Transvestigation and the bizarre conspiracy lore it has become embedded in is one of the many outcomes of a decade of stochastic terrorism.