While the smaller pistols are generally easier to conceal it is also true that he smaller the pistol, the harder it is to master.
That being said, my daughter who has nearly zero experience with a handgun recently bought a S&W m&p shield 2.0 (a sub compact) in 9mm and is shooting it surprisingly well with just a couple of weeks of practice. I find it (as did she) to be an amazingly easy shooting gun that is very concealable with just a loose hanging t shirt and iwb holster.
I believe that the Shield is a pistol you should strongly consider.
Just took a non-shooter young lady shooting on Saturday. Zero handgun experience. Started with 22lr, Smith 41, and within one magazine she was grinning and tumbling cans. Smith 317 next and cans continued to tumble. She shot several boxes before moving up. No human-size target would be safe and the 317 is about as tiny as they come.
Of course she had no bad habits before we started... and did not know tiny handguns are a problem.
