I finally decided on a .38 for general home defense. I, like a lot of folks here, have a choice of several calibers. Still, for my wife, mother, younger son, a .38 is best in my opinion. There is no safety to remember, no racking required for weaker hands, no separate magazine, and no scary recoil. The bullet is large enough to do what you want it to do. I have a 3 inch barrel S&W and two snubbies made by S&W. I use wadcutters because of the low recoil and the softer lead bullet. I really would like to use the +p but the others who may need to grab a pistol do better with the wc. I read about these on this and THR websites over the years. My wife can easily control the snubbie with these bullets. We both have become accurate with these.
I purchased a police trade-in Model 10 S&W in the past and really like those. They have a 4 inch barrel and hold six rounds. They were carried a lot and shot a little.
The new S&W pistols are good pistols and you have several to choose from.
Whatever you get, you owe it to yourself to practice until you feel comfortable. Get a holster for it just in case you need to walk around armed but with free hands.
After getting a pistol, or simultaneously, get a Mossberg or Remington 870 home defense shotgun. They are simple guns to operate with a little practice. My opinion only! There are lots of good ideas on this thread. You may get hooked on guns, as many are on this forum, and buy more than you really thought you would.