Ok...well, I was at a restaurant today and the waiter came up and when we said we were ready to order, he said, "Ladies first!" and everyone looked at me....I just said, "No thanks." and ordered after everyone else but this reminds me of a situation a few weeks ago where a lady yelled out to me and my mom, "Ladies (insert stupid advertisement that I don't remember)!" I wear loose clothing, sports bras, I have short hair and a more or less masculine face yet EVERYONE CALLS ME A WOMAN. How am I supposed to respond to this?! I know it sounds stupid but it's really bugging me... :tears:
I dunno. Being bigender I get "he" most of the time even if that's not how I feel inside. I generally just shrug it off.
Depending on the situation, I either ignore the person completely or correct them. If it's someone shouting an advert at me (I have mutiple times had someone say something like "ma'am, we can give you beautiful hair extensions!" or something at my local shopping center) I completely blank them and act as if I didn't hear/they couldn't possibly be talking to me. If it's someone who I need to respond to but am probably not gonna see again, like the a waiter, I ignore until they say something else/make it clear that it's me they were talking to and then say "oh, me? Sorry, I thought you said lady/whatever-term-was-incorrect" then carry on with whatever response I needed to give. I don't directly state "I'm not a girl", more of imply it. I don't care if they fully get the message or not cause likelihood is I'll see them for an hour and then they'll be gone. If it's someone that I'll be seeing again, like someone at work or in class, I say "Wait, lady/whatever-term-was-incorrect? C'mon man, I'm a guy" in a voice that makes it sound incredulous that someone got it wrong. I don't know if any of these are viable for you, it's a hard time trying to present as gender-neutral since without a doubt people will throw one of the gendered terms at you. :/ People need a wider awareness of non-binary identities.
I like to have a sort of running joke in my mind where I pretend I'm a secret agent and my cover is a girl, so when people call me a girl I just laugh it off in my head like 'oh ho ho, if only they knew.... " It's kinda silly but maybe something like that would work for you if you're not out enough/confident enough to correct people.
I wish I could help you, but this really gets me too. >.< I'm not really outwardly claiming to be male yet (besides having a male hair cut and exclusively wearing men's clothes like I have been for most of my life...but that doesn't really mean anything to anyone unfortunately) and not on T so I imagine it is kind of the same as being nb i.e. you don't identify as female but people still refer to you as female and there really isn't much you can say about it in situations like this. What I do (and this probably isn't healthy or productive in any way) is just give them a dirty look and be like "naw", and then in my head sometimes I will make it into a game where I keep a tally of how many times I am unnecessarily gendered in a day so that way it almost feels like you are winning a point every time.
This is exactly what I do, because currently I'm not in a position to be passing. But like above advice, I'd recommend ignoring the comment if you can or correcting them. Most of these people are just trying to do their job and should not take it personally to be corrected.