I got a kid Mani and pedi and one of the workers where doing my feet and she told the lady who does the facils that I was a big girl and that there is no way I was 11so she basically called me fat me and my mother w me and my

You may be misinterpreting what she said. You may be a big 11yo which it makes it hard to believe that you are 11. I know the feeling. My son is a big 9yo. I think he looks normal and then when I see other 9yo, I'm like dang, my son is big. I also will tell the 9yo, dang, you are small for 9. I probably shouldn't do that because it could lead to insecurity issues. You may just be big for your age. It's okay. Everyone body develops at a different rate and there isn't anything wrong with that. The workers may not be used to seeing an 11yo your size. Just think of it as everyone else is just trying to catch up.

I told my mom

The probably was referring to your height. You should have told your mom so she could've let them know