Why are people calling me ma'am at 17

Growing up is so weird. Like in my brain, I still feel like I'm 14 or something. I have a job now, and I know I don't look like a child anymore but ZANGGGG why are people coming up to me being like, "Excuse me ma'am" LIKE HELLO?? I'M SEVENTEEN?? which is kinda old I guess and maybe ma'am-worthy but it still feels weird.