At my age and in my physical condition, whatever I have is going to be lots better than nuthin'. Having been on the business end of a couple of guns, I'm of the opinion that even a 22LR looks pretty big when it's pointed at your face. Having made something of a study of this for a trio of decades, I'm of the opinion that, barring a central nervous system shot, it's going to depend more on the BG's willingness to keep going than much else with most handgun sized self defense platforms. Yes, a standard 38 Special RN might not even slow down a determined attacker, but a 22LR has stopped a lot of BGs in their tracks. Use what ya got. 1 good hit from that 22 is lots better than 18 misses with a Glock.
That being said, I carry everything from a 22 to various 35 cals to 44 and 45 cals. I did ditch the 25 Auto, mostly because I couldn't hit well with it despite my affection for it's size and function. I prefer to stay away form crack houses, biker bars, other peoples wives and I've completely given up selling heroin on the street corner, so I don't have to fight hoards of mutant zombies biker Crips these days. All told, that little Smith Bodyguard 38 feels good in my pocket and the Star PD still fits my hand well.