I personally carry a full size glock 21 .45 ACP with 185 Grain hollow points in it. One of the really nice things about the .45 ACP is it is already a sub-sonic bullet and has a large mass. I go with the smaller 185 Grain because I live in an apartment and I don't want the bullets going through the walls. I will warn you, that 9mm is notorious for going through walls and also for ricocheting. I helped get guns for both my parents and they decided against the 9mm after watching videos of even the 9mm hollow points going through two sets of walls. Although the 9mm has a huge amount of different types of ammo and you can find ones that won't. When I was helping my mom pick out a gun, she tried tons of different ones before settling on .357 magnum revolver. She often loads it with low grain .38 special hollow points. Most experts recommend heavy revolvers for women because the extra weight forces you to engage your upper arm muscles rather than controlling it with your wrists, this is especially important in self-defense situations where there will be high amounts of adrenaline coursing through your body which can cause your hands to shake. Furthermore, revolvers just plain work, they aren't complicated you put the bullets in and pull the trigger and it shoots, no extra buttons or having to worry about racking the slide. So although I am in no way an expert, I would agree with the experts that you should get full size revolver. My girlfriend's mother has a full size ruger security 6 in .357 magnum and she loves it. I have shot it before and it really has a great weight to it. All in all make sure you get something that won't pierce walls (low grain, hollow point ammo), will stop the attacker in his tracks (not a .22), and something that you like and will be comfortable with to practice regularly. I hope that helps and if you need any help or want to try any of the tons of guns I have let me know