What Breed Is My Dog?

My dog is only 4 months old. She is very relaxed, but if kids are playing or other dogs are playing, she becomes active. Otherwise she is very calm. Her tail has a half circle curl at the tip. It points down on her back and forward, but on the side of her body. Otherwise it is very long. Her ears fold to sides and point down or slightly back. She has webbed feet. Her fur is black around her eyes.

Sheepdog?
Collie?
No idea..