Unless they're a child prodigy, it's very unlikely. It's better to start a little older so they actually understand what they're doing and why technique is important. Martial arts is not like soccer or tee-ball. The basics take a lot longer to learn and can be frustrating for a kindergartner.

Crazy that the people who harp about universal Healthcare don't want it unless zelensky says it's okay

An assailant can easily cut you up after getting pepper sprayed. Pepper spray sucks ass, but you can fight through it for a while. I personally have nothing against martial arts, but it takes a good 5-10yrs of training to be any sort of combat efficient. I would not advise sending a yellow/orange belt into a knife fight lol.