Dan Carlin discussed gun laws in relation to the Charlie Hebdo / antisemitic attacks in France recently. He made some well thought out arguments for and against gun laws (this episode). One of the for arguments he talked about was that gun ownership can be a human rights issue, a gun acting as a device that equalizes you with all others. He used an example not unlike yours. You have the right to defend yourself with the best equipment, which is a gun in your case. While the idea itself wasn't new to me, I hadn't fully grasped that it is such a fundamental argument for proponents of gun ownership. I can understand why you'd buy one. Personally, I don't trust myself with a lethal weapon, and I do think a society without ubiquitous gun ownership is less violent and better to live in. But if I were in your situation I'd probably do the same as you.