Need advice

[Ruby]

Hi, I recently purchased a chow puppy who is now 12 weeks old. I was assured by the breeder that she was full breed chow but I am having my doubts. Her ears are still down and don't seem to be making any moves to stand erect. She has a full black tongue and her tail is carried the correct way. I will attach a photo and any advice would be greatly appreciated. Thank you in advance