It's not your fault dear. And yes a child could dart fast enough to be hit like that too. My mother hit a little boy once who darted out in front of her from between parked cars. Broke is leg, but the dad knew it wasn't her fault, he was following daddy. But of course she felt awful, only going about 22 MPH in a 25 zone. And saying it could have been a child or a person, like it is not the same thing to hit a dog!
In my opinion, there would be no difference. Try to keep it in mind, it is not your fault, and of course you would never hit a dog if it was in your power not to...
~Melody