Normal to call a 21 year old "ma'am"

I've grown up in the south and it is just customary. I was taught to say that to anyone older than me in a professional setting and out of respect.

Naw, I'd just call you kid.

I do this too.

Ugh I hate to be called ma'am sounds so fricken old! But remember you can't please everyone. I don't call anyone anything like sir or miss or ma'am, I just go " hey you".

I did that once when I was 12, but the lady who was working there got all offended and so I don't do it anymore to people 21-33...

I pretty much call any female ma'am who exhibits professional behavior, even if they appear to be my age or younger. And sometimes kids too, but in a jestful or scornful way - "excuse me, ma'am!".

I've been called those things by strangers. I called a woman "miss" once, and she waspishly replied that she was a "Mrs." So now I usually stick to ma'am

I do. It's more of a common southern courtesy. I grew up in central Texas, in the heart of a military base l, and it was common to refer any woman, doesn't matter age or race, ma'am or miss. When I moved back to southern Cali. I noticed the woman here don't like to be called ma'am since it makes them sound old, I guess?