My main concern is friendlies in the house, you need to be aware where they are. So for that reason, you may want to load down.
You may want to go to one of those mobile trailer enclosed ranges to get an idea, if you have never fired a gun inside an enclosed space. Most defense shootings take place at distances of less than 7 yards, according to those who study such things. Our local trainers say this and recommend that you use that range and focus on gun familiarity most. They also recommend pistols as the primary defense arm, which I adhere to. It's too easy to get a long gun taken away in a close encounter, so they say.
Number 3 buck or even #2 bird shot is still quite deadly at close range. Either would be fine for defense. I use a compact pocket-able pistol in 9 mm with Corbon defense loads. With the compact, you can pocket the pistol if need be, and see what the commotion is, of course, situation depending.
The call 911 route first is best ... if you have the time.
As they say with opinions, everyone has one, so practice and make your own choices are generally best.
“You may want to go to one of those mobile trailer enclosed ranges to get an idea”
Good idea, I have been in indoor ranges and they are not pleasant. Another consideration is that anyone within 10 ft. can kill/disarm you, even if they don’t have a firearm. My backup weapon is a .32 magnum Ruger, I think it is as effective as the .38 special (and holds one more round) and is far more comfortable to shoot than a small frame .357 magnum.
When seconds count... the police are only minutes away!
LLS