Maybe you could find a Krav teacher and ask them what they recommend as a way of working up to it?

Everyone knows how to defend themselves. You just need to find out how to do it effectively -- some defences are better than others. Just, um, don't, you know, start carrying a gun everywhere. (You'll inevitably shoot the wrong person, probably yourself. Or be arrested for carrying. Unless you have an open-carry permit and I don't think they give those to civilians.)

I always like to help!