Any loaded revolver is faster and easier to pull out and fire in high stress situations.
Revolver: Aim, pull trigger
Automatic: Determine whether or not round is in chamber, pull hammer or rock slide, aim, pull trigger
Yeah, you could always leave a round in the chamber and half cock an auto I suppose... but revolvers eliminate that complexity.
Stop giving out firearms advice as you don't know what you are talking about.
Rock slide? Are you playing Metallica to it or something? It's rack the slide. If you are carrying a firearm, it needs to have a round loaded and ready to go.
Any of my semi-autos that I carry are allways loaded and ready to go. None of them have safeties to worry about. just draw and fire.
I can't believe how many people will say don't carry a semi-auto with a round in the chamber it's not safe, you should carry a revolver. When they don't think about what they are saying. A revolver is going to have a round in every cylinder and the hammer is going to be down on the revolver while carrying.
OP. Your best bet is to go to a gun show and handle as many weapons as you can. Note the ones that feel the best in your hand. Go home and research those models and check the reliability of the weapon. Then purchased based on that. Caliber is irrelivant. Shot placement is. Modern jacketed hollow points all have excellent penetration and expansion characteristics that make them good choices.
Go out and practice, practice, and practice some more. Make sure you are comfortable with whatever you choose and can manipulate any controls on it without having to look at what you are doing.
Personally I suggest paying a bit more money and getting something like a Sig or H&K.
For your 1st firearms ownership experience you want it to be a good one. If you buy a POS it can sour you to the whole thing. The Sigs and H&K are going to typically have better recoil characteristics, are typically more accurate, and are more reliable.
Whatever you do, don't get a subcompact as your first gun. Recoil is harsher, and sighting on a shorter sight radius will make your groupings much larger.