Where did you get the dog from? Real farm Border Collies are all 'mutts' in a way. They come in several sizes, colors, fur lengths, etc.
But your "pure bred" is only about looks, so anything less than their perfect picture isn't a Border[black/white, long haired or short, 35-45lbs].
Looks like there's some cattle dog mixed in. For around $60 you can have a DNA blood test done and you will know for sure.
I vote border collie. The color varieties are so varied that you never know what you will get. I can say that I have never seen one that striking. I have seen something similar in brown and white but not as much white. You really have a unique baby I bet you get lots of comments. Very cute.