Please consider what I am about to say.
My rule of thumb is carry the largest gun you can comfortably and effectively conceal. Bigger autos are much easier to make multiple accurate shots with than all these tiny guns everyone seems to love. The weight helps control the recoil, the grip accommodates all of your fingers, and the sight radius improves most shooter's accuracy.
Also, tiny guns, save for a few, are NOT fun to shoot. You need to practice with your carry gun as regularly as possible and if you don't enjoy shooting it you may just opt to shoot something else on range day. I also find larger guns MUCH easier (faster!) to draw from a holster because of the larger grip. I don't want to be fumbling around trying to get a decent grip on my weapon when fractions of a second count.
The only reason to carry a tiny gun is if you can't dress around a bigger gun or are just so uncomfortable carrying the extra weight around that you would consider leaving the bigger gun at home.
I'm 5'6" and have no problems carrying a 5" 1911 or Glock 19 every day, winter or summer. Those are my two EDCs and I conceal them just fine. Someone with above average attention to detail may be able to spot me but 99% of the population won't. I have a very well made belt and holsters for each gun and I honestly forget they're there some times.
IMO you were on the right track to begin with. I personally think the G19 and SR9c are about perfect carrying size. Not so small as to be difficult to shoot well but small enough to not have to dress around them as much.
All that said, if you think you may get sick of lugging around a bigger gun all day then by all means, buy the gun you WONT get sick of carrying ever. A tiny gun that's hard to shoot well is better than no gun at all.
