Based on research, it looks like around 30% of Americans own a gun [1]. So you may just live in an area with a lot of gun owners. Also, not everyone owns a gun for the same reason. Some for protection, some for hunting, some for antiques, etc etc. I've owned my house for a few years and last year I found a couple of shotguns tucked away next to a bookcase in a closet. I eventually got rid of them, but for a few months I would have technically had to raise my hand for that question.
This is a poll done by Pew Research Center, not a registry of guns that the government knows about. Obviously there is still a possibility that people are lying to pollsters, but there are extremely frequent speculations about things like that (e.g. the "Shy Tory Effect") that almost never end up skewing things by more than a few percent.
I think President Trump proved people are lying to pollsters more than ever. Also Americans lie about guns quite a bit. I've even meet some who don't consider handguns as real guns or call them baby guns.
[1] http://www.pewsocialtrends.org/2017/06/22/the-demographics-o...