Does anyone have a recommendation on the earliest age to start strength training and conditioning?

Hello Michael Bowman,
There is no age limit in my book; farmers have their children out and helping when the children can walk. We do not need to use weights, bodyweight is enough until good form is practiced autonomously. I prefer very light weight until the child is thirteen years old. Slow and steady wins the race. It is most important to teach good habits that will last a lifetime.
Enjoy the youth,
Natalie aka NAPS 2 B Fit.