I'm missing several fingers on one hand, and there have been a decent amount of people who didn't notice for weeks or even a few months, even when interacting with me multiple days a week. It certainly never took 9 months, though; the max was about half of a semester in college.

I had a coworker with no hands. I noticed right away. I did fail to notice he also had no feet for about a year though. I probably shouldn't have blurted out "You have no feet?" Really loud when I finally did notice. He did a really good "Holy cow, where's my feet go?!" though.

I had a colleague who had only one arm. I think it was amputated above the elbow. It took me 3 months to realize he has no arm. We were working together in the theater, he was an actor, and he was rolling my cigarettes all the time because I did a bad job myself. He rolled my cigarettes and I didn't notice he had one arm.

Tell her she's an adult and she should use her words.

Maybe don't phrase it quite like that unless you want to be single.

I had a colleague missing a hand once, and it me more than 9 months notice, even though I saw them in the office each day...

She could also talk like a normal person and reserve the 'signals' for silly shit that doesn't matter where "Well, it's a bit of a bummer he didn't pick up on it but nothing needed."

Dealt with that shit for years with my ex. Talk to me, or it doesn't matter currently and not worth being mad about.

I got a new co-worker once. He was a drummer. I try, but I can't do rolls and have shitty symmetry. We're going drinking after work, so on the way there I ask him "how do you get both hands to play the same speed? I keep fucking it up with one side" I think he gave a basic explanation, and we changed topic after a while.

Later on, at the pub, I realise he's missing several fingers on his left hand.

I then want to die of embarrassment.