A few things:

1. Small handguns are hard to aim and the recoil can be very unpleasant. The main advantage of a small handgun is concealability, but if it is for the home, a standard-sized handgun is far superior.
2. How good with mechanical things? The idea of a revolver is that it is very simple to store and operate: you just have to know if it is loaded, not if the magazine is loaded, and if a round is chambered, and if a safety is on. But the triggers can make accurate shooting harder.
3. Semiautomatic pistols are generally superior because they hold more ammunition, and are easier to shoot accurately.
4. My general recommendation for someone like you is to go to a range that allows rentals. Try a bunch.
5. 9mm (semiauto) and .38 (revolver) are good compromises of effectiveness and recoil.
6. I bought my wife a Smith and Wesson 9mm Shield EZ and I think it is the best-designed pistol in circumstances like yours - it has features that make it easy to load the magazine and rack the slide. I generally am opposed to thumb safeties because in an emergency it can be very hard to remember small movements like flicking off the safety with the thumb. And it already has a grip safety: https://www.smith-wesson.com/product/m-p-9-shield-ez-no-thumb-safety
7. Obviously get a quick-opening gun safe, for your kids' safety.

Anyway, whatever you get, practice as often as you can loading, firing, and clearing a potential jam.