Personally, I would say that instead of 3 handguns, you should start with only 1 of them, in 9mm, and get a .22lr conversion for it. Having the 22lr option lets you work harder on sight picture, trigger pull, grip and stance without having to think about recoil and without as much fatigue from managing recoil. I'm talking about shooting hundreds of rounds a day, several days a week, to work on those things and fine tune them.
Then, get yourself a good 9mm reloading setup, single stage or turret press, not looking to bulk load, looking to precision hand load, then you can develop a custom load for your handguns, once you get to the point where you can out-shoot bulk ammo precision
Personally, I would start with something beefy, like a nice Browning High Power (brand new with adjustable sights, not surplus or anything) Throw some custom grips, a custom target barrel and a set of wolf match springs in there.
You could also go for a Kimber or Wilson 9mm if you want, but if you want to actually develop some skill, you want something you can shoot shoot shoot and then shoot again, and the BHP will stand up to that kind of round count.
A true custom fine tuned pistol is NOT something you use to learn how to shoot with, it's what you get when you have enough skill to out-shoot a good solid workhorse pistol like a BHP.
Forget a glock, not great to learn on and won't stand up to the 1000s of rounds that you'll have to shoot to develop some serious skill.
Then, once you can out-shoot the pistol, get something higher end like a Wilson or Kimber or Baer.
Think of it like this, would you teach a 16 year old to drive in a manual shift ferrari? Won't be long before you'd need a new ferrari, and maybe a new 16 year old too... but, it's an awesome car to learn to drive well once you are already an expert and you've worn out a few cheaper cars doing the 500,000 km that it took to become an expert.