You can introduce them to meditation from early age on, they just usually lack the patience to do it for longer or intense, when they are small. I myself start

You can introduce them to meditation from early age on, they just usually lack the patience to do it for longer or intense, when they are small. I myself started meditating on my own, when I was 11/12 so that is definitely an age, when you can do it serious. My own kids (< 5) are too small yet, that I would do serious meditating with them, but some sort of pre exercises, like just sitting still in nature and observing, do work since the beginning. Don't push them obviously. Rather give them a chance, to explore mindfulness and consciousness with you. I can also recommend Tai Chi/Qui Gong as an more active path towards it.