Is this what stealth feels like? (Maybe NSFW)

Okay, here's the background. I've been out as MtF for a few years now, and I don't really feel all that uncomfortable letting people know I'm transgender (I don't correct customers at work, but that's because almost EVERY walk-in there calls me sir and it'd be exhausting to tell them all I'm a ma'am). I play Overwatch a LOT and just started making a new group of friends on the PC version. My Battletag is literally just my name, cause I like feeling validated when total strangers refer to me by it.

So yesterday we were having just our usual weird-person banter, and somewhere along the line the conversation got to genitals. Someone remarked that in the group, four people had a clitoris and one had a penis ("you're outnumbered, bro"). When they said that, I realized that they were lumping me in with the clitorises. I was kinda quick to let the group know that I was transgender, and they were totally fine with it and corrected themselves, and we went about our normal conversation.

But I realized something this morning. That was the first time I can think of that someone actually showed an assumption I was a cis girl just from my voice and name("I totally never would've guessed!" doesn't count). And if I wanted to, I could've just went along with it, not said anything, and had them continue in their assumption. I've always been a fairly honest and open person, so I never really had the intention of going stealth when I first discovered my trans-ness. After all, being trans is part of my identity. But I do kinda wish I'd taken the opportunity to see how it felt to be seen as a cis girl.

If anyone else has had the opportunity, of being fully out as trans but given the chance to have new people assume you were born with a vagina, how did you react?