For personal defense, I start with 9mm and work my way up.
While I think 22LR is a great way to learn to shoot a handgun, it's garbage as a CCW and personal defense round.
Most 22LR revolvers are similar in size to small 9mm's (and identical to 38 spcl), you can't out engineer the fact that revolvers will need a cylinder, most shoot from the top of the cylinder, and therefore are fatter and taller than a single stack semi of just about anything and nearly the same size as larger caliber revolvers.
That and the round is just weak. 38 spcl +P is good for a revolver and 9 mm for a semi. Work your way up from that for personal defense.
...and, no, I'd never intentionally step in front of a 22LR or a 380 ACP, like all the arguments always default to, but that's irrelevant.
...also, most subcompact carry revolvers have terrible triggers, worse than subcompact pocket 380s and nines.