[Gatofeo]

My opinion: to learn the basics, start with a double-action .22 revolver.
This will teach you sight alignment. Ammo is cheap, to encourage practice.
The cylinder swings out for easy loading and unloading, cleaning and checking (no hidden surprises in the chamber, a la semi-autos).
Revolvers can accommodate a wide range of types of ammo. They're not dependent upon ammo working within a narrow range of pressure, or prone to jamming.
Revolvers may also be fitted with a variety of grips of different shapes and sizes, to accommodate different hand sizes. True, revolvers are limited somewhat by their frame size and shape, but not to the extent that semi-auto handguns are.

The Smith & Wesson Model 19 .38 Special is a fine revolver. I have one myself and enjoy it. But I enjoy even more my S&W Model 15 with 4" barrel. It is essentially the Model 10 but with adjustable sights, so I may adjust my sight picture to where the bullets are hitting on target. This enhances accuracy and builds confidence.
The Model 10 is fine, but has fixed sights. It is factory regulated to shoot with the front sight covering the area where 158 gr. lead bullets at about 800 feet per second will impact, at 25 yards.
My adjustable sights are set so the bullets are hitting just above the front sight. This allows me to see the target, rather than having it covered by the front sight.
This setting is commonly called the "6 o'clock hold" and is used by target shooters. But I also used it in the U.S. Air Force when I carried a Smith & Wesson Model 15 .38 Special. Being able to see the tin can or bullseye hovering above your front sight, and knowing that the bullets will go into the area just above it, is a distinct accuracy advantage.
Should you decide to use bullets lighter than 158 gr. lead (say, 130 gr. Full Metal Jacket ammo currently popular for plinking), you'll find that these bullets hit below the point of aim of a Model 10 and its fixed sights. You'll have to compensate by aiming above the tin can or target, to raise the bullet impact up to hit the target.
This gets frustrating, especially for a newcomer.
With the Model 15 and its adjustable sights, you simply elevate the rear sight a few clicks and the group of 130 gr. bullets are hitting just above your front sight.
Adjustable sights are worth the extra money.

I still suggest a good, .22 double-action revolver with adjustable sights. Ammo is cheap, and the adjustable sights encourage greater accuracy.
Plus, it's a gun you will never outgrow. A good .22 revolver remains a useful tool for the rest of your life.
Later, you can go onto a .38 Special if you wish.
And don't overlook the .357 Magnum. Many new shooters don't know that you may safely fire .38 Special cartridges in .357 Magnum revolvers. The .357 Magnum is essentially a .38 Special with a brass or nickel case 1/10th inch longer than the .38 Special. This was done, when the .357 Magnum was created in the 1930s, to prevent the more-powerful .357 from fully chambering in .38 Special revolvers. The longer case won't go fully into the cylinder, so the cylinder cannot be closed into the frame.

The .38 Special or .357 is a very versatile cartridge. You may purchase shotshells for it: they carry small birdshot in a plastic housing, creating a mini-shotgun effect. So little shot is held, however, that these cartridges are only good for small animals (snakes, rats, rabbits) at no more than 15 feet or so. Still, loading your revolver so the first shot fired is a shotshell is a good practice in rattlesnake country (in which I live, and employ the same practice).
However, I don't shoot snakes on general principal. I just walk around them. They have their place in the scheme of things, too.

The .38 Wadcutter bullet typically weighs 148 grs. and looks like a miniature oil barrel. These are meant for target shooting, but can be useful for self defense in the home, where you don't want to penetrate multiple walls and perhaps hit an innocent person in another room, next apartment or outdoors.

Perhaps the best-documented self defense .38 Special cartridge is the 158 gr. lead semi-wadcutter hollowpoint +P, as made by Winchester, Federal or Remington. It's also called the "FBI Load," "New York Police Load," or "Chicago Police Load." This full-power load has a good reputation for stopping bad guys, especially from revolvers with barrels of 4 inches or longer (the longer barrels helps to burn the extra gunpowder, thereby increasing the velocity over a 2" snubnose).

I own numerous semi-autos and revolvers. I shoot both. Through the years, I've taken many people out and introduced them to the basics of pistol shooing. Invariably, they like the .38 Special with mild, 148 gr. wadcutter loads or 158 gr. lead bullets at standard velocity (850 feet per second or so).
They also like .22 revolvers. Many get confused with the operation of a semi-auto, and some are distracted by the slide coming back during firing.
The revolver is more "user friendly." And of all the revolvers, the double-action with its swing-out cylinder is friendliest of all.
Of all the cartridges, the .22 is the most "user friendly" for beginners -- and experienced shooters.

You'll pay about $20 for 500 .22 cartridges. That same $20 will get you about 50 .38 Special cartridges. The ammunition savings is significant and will allow you to practice more.

I have never met a beginner who didn't like, and take to, a .22 double-action revolver. They're simple to operate and easy to check for status.

Sorry for prattling on so much, but it's a topic dear to me because I've introduced many beginners to pistol shooting.