Okay, I'll play.
How soon can I arm myself? Depends on where I'm at in the house. Max of 30 seconds, then pump action ready to go.
No other family members.
911 will be called automatically because if you've broached any opening in my house, a deafening siren goes off and it goes to alarm company then dispatch. No need to touch a phone. If it's a common BG, they will run with the alarm, I hope.
Door are (now) always locked and alarmed with me inside. Except now, cuz the pizza guy is coming but there happens to be a gun 6 inches from my hand. Didn't plan that, just happen to be handling firearms at the moment. I'll drop a towel over it before I go for the pizza guy/gal.
I hope that after that the OP is done thinking about someone kicking in the door right now, he can move on to something more relaxing. I'm planning on watching the tube with the pizza and forget about the BG. Preparation allows for that, I hope.