Let me repeat so you understand. Get some training from a qualified firearms school. Spend the money so you know exactly what has to happen when things go bad.
A good school will not only teach you how to shoot but when not to according to the legalities in your locale.
I don't anticipate a violent home invasion for the next 30 years or so, we don't have that type of crime stats here. DUIs, "texting while driving" and ice storms are the kinds of disaster we worry about.
Maybe you should take some ice storm and Arctic weather survival training...invest the money and be safe.