Hello, it's my first post on this forum and I am so happy I found a community like this one. I own a big yorkie, he is 14 pounds( 6 kilos) very muscular and strong too

I went yesterday to Pet Expo, wanted to buy something nice for my baby... aaand a very "smart" lady (she was representing Hills brand food) told me that my Max is a mix yorkie because it is impossible for a yorkie to be that big... it is not the first time. Many people do not know anything about yorkies and their history and they still talk and argue with you. Please look on my pics with Maxy and tell me what do you think? I have no idea what kind of yorkie mix could he be?