What Breed Is My Dog?

We adopted Zora here from a rescue in January of this year. We were told she was eleven weeks old at the time, which would put her at a little over four months old now. Our vet, however, said he thinks she is a bit older as she's already gotten quite a few of her adult teeth. He believes she is 5 to 6 months old. We were told she was a Lab/Golden Retriever mix, but she is not getting as big as she should for that mix. She's wonderful either way! But, she has been very timid around new people. We've been bringing her out to dog-friendly places to help socialize her, but I do think understanding her breed a bit more would help as well.

Our vet thinks she may have a bit of Chow Chow in her due to some black spotting on her tongue, as well as some fluff on her back. Chow Chow would make sense to me from what I've looked up due to their pretty reserved pack-like tendencies, but that still wouldn't explain how small she is! She was 21 lbs at our last vet appointment, she's probably between 25 and 30 now. Any thoughts?

By Sally W.