Are you familiar with Krav Maga? It's a military-based self-defence and fighting system.
I am not familiar with Krav Maga. Is this a sport?
It's more of a self-defense technique. It combines a bunch of different fighting styles: boxing and wrestling and street fighting.
Where was this technique first invented?
It was actually developed for Israeli military personnel. But since then, it's spread all over the world.
Can older people like me find a place to take classes in the self defense techniques?
Absolutely! Although Krav Maga emphasizes aggression and some offensive maneuvers, so it may not be a good fit for you.
How is it possible to combine all of those styles into one method.  It sounds very difficult
It actually adopts the most simple techniques from those other styles, so it's rapidly teachable!