Krav Maga for 69 yo in case the Zombies come?

Get yourself an osage orange bow stave from Ebay. Make a great staff from that. Hard to believe people are still selling osage orange wood after all these years on Ebay. You could always go outside and hunt some down if it grows in your neck of the woods. After it cures for a season or two, just shape it how you like. For added strength, not that it's needed but to make it like steel, wrap it in sinew coated with urethane. I'd thin it out a bit to compensate for the added weight.

Back years ago when we taught rape prevention, the very best thing anybody can do is to remain vigilant. Never place yourself in a situation where you can be blind sided and never expect strangers to just be friendly. If you have your guard up and refrain from being in close proximity to others who could pose a threat, you're preventing the problem before it ever begins. If you are attacked, rip and tear at the fleshy bits (eyes, nose, testicles) until you break free and run to safety. And if you yell "fire!" you will attract more attention. I will say that all those martial arts classes can pay off in the long run. Just keeping you limber and active is important, but also maintaining your balance and focus in a fight can be critical.

It doesn't take a martial arts expert to remain effective, just common sense.