You can keep your guns. As long as they are long guns with internal magazines of five or less capacity. All others will be banned.
Not sure what fantasy world you live in but they won't be banned. Not in your lifetime, at least.
Can you defend your home with say, five shotguns and five rifles all having five rounds each?
Possibly. But in the world of unicorn farts and rainbows that you go to when you sleep, even if you managed to get rid of all the legally owned firearms, criminals would still keep their illegal ones.
But perhaps owning those fun hand guns and the AR15 toys is more important than children's lives.
Owning those hand guns and AR15s is very important to children's lives. Mine. That's why I will keep them.