It's certainly worked as far as school shootings are concerned. There hasn't been one since 1996, and mass shootings themselves are similarly rare (there have only been a couple since then, not in schools). There is obviously still gun crime on occasion, but it isn't widespread. So I'd say more than semi-worked. At least three-quarters, and well worth it. There was universal agreement across political parties and the population in 1996 after the Dunblane massacre, so we massively tightened our already pretty damn strict gun laws.

But in the US, gun culture is entirely different (in need of urgent reform, but that will take decades, and the population have to be willing to do that in the first place). Therefore, since I'm a practical, pragmatic person, if I lived in Florida alone I would also seriously consider owning a gun.

So essentially, I agree with your stance on owning a gun for protection.