When is a good time for proper training?

My son is 3 in October this year, I have him just doing some punching and kicking in the air but what age should I begin his personal training?

I don't have children in my Children's class younger than 6 (that's on exceptional circumstances) its normally 7. But as I can teach and train with him daily when do I start with his training?

Adult's Class is aged 14 upwards
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