You have to start with a .22, to save money and speed up the learning curve. Then, after you are highly skilled with the .22, you can move on to the 12c a shot 9mm. The lower levels of blast and flash with the .22 help prevent the inculcation of flinch. When you are learning to hit really fast, either on the draw or just "raising" or pivoting-traversing with the pistol, and getting repeat hits at the rate of 4-5 per second (as you are likely to need to do, regardless of your gun or load) it's very common indeed to acquire a flinch.

So, even if you can afford to waste an extra $100 per 1000 rds of practice ammo, there's no reason to do so, and every reason to learn first with the .22. If you can't do a given exercise, in a given time-frame with a good.22, there's simply no way that you can do so with a centerfire, any centerfire. The centerfire just makes things harder, and of course, more expensive, and there's no reason to bother with it, until you are a master of the .22.