Before the thread gets away on any other tangent, I do want to say that killing anyone, even in self defense, is likely going to be one of the hardest ordeals you will ever face. And wounding someone in self defense, even if fully justified, will be even worse.
You will be both praised and vilified, your life will be put under a public microscope in a hostile press, the police will treat you as a criminal, at least until it is proven you are not.
Even if you are not criminally charged you will likely face a wrongful death civil suit. Get a lawyer as soon as possible. It is a good idea to carry legal insurance, it is essential if you own a firearm.
You will have to deal with varying degrees of doubt, regret and exultation, which will revisit you, regularly. Find a good counselor if something like this happens to you or a family member and go whether you think you need to or not.
That all of the above will happen should not dissuade someone from actually defending themselves and their family. If you take the conscious step to be prepared, be prepared all the way.