Kittens from the Milkman's Cat

I was out of town during the end of May, first of June. When I got home, I found my Himalayan cat, Milan, in heat. I hadn't realized she was old enough yet. So, I took her to the vet to get a shot that takes cats out of heat till they can be spayed. But, here we are, 11 weeks later, with kittens from the black Persian "milkman" cat! All the kittens are black. I just can't believe it!