Sir/Ma'am

I work at a retail store and I mostly work the cash register. Now, my hair is long, about down to my shoulders, and I'm still 25, and I have been working on my voice so that talking femininely is becoming more common. Now it seems that it is 50-50 on whether a customer who will say sir/ma'am to the cashier will say sir or ma'am. Both cases make me nervous, but for different reasons. I dislike being called sir and being known as sir, and there is a lot of people who are close to the manager and I'm still presenting as male, so the manager refers to me as male, so they start saying things like "What's up man?" or "Hey buddy," which I hate. I don't really react to them, which I know just puts myself down in their eyes, because I'm still 25 and I look young, and I'm a guy, so I'm supposed to get into that kind of talking too or I'm just a stuck-up, right?

Now there are customers who address me as ma'am*, but I get nervous then too, because I still have telltale signs of being male, such as Adam's apple--which thankfully isn't too prominent, though still pretty prominent for a woman--lack of breasts, and wide shoulders compared to hips (though my hips are usually behind the counter), so I'm worried that if I don't correct them and they see those telltale signs, they will call me sir while wondering why I didn't correct them when they called me ma'am. I think I have already seen signs of people being somewhat shaken by the fact that they could call me either one and it wouldn't make a difference, which might make them think I'm an attention seeker or self-hating. (It seems both men and women will call me ma'am, though it seems men more than women, and more women seem to call me sir.)

Anyway, that is the story of that. Any comments from anyone else?

* I can't hear too well, I think, the difference between man and ma'am, but I think that if a person is speaking politely, as opposed to ghetto-like, they are saying ma'am.