I am sent many messages from parents asking how to introduce children to spiritual practice, what type of things could they do and when is the right time.
This is of course very personal and every situation and family unique. When it comes to the question of timing my advice is be led by your child. If you work with crystals and they show interest, start there! Maybe get them their own crystals and teach them some basics. If you practice yoga and they enjoy watching you, encourage them to try a few basics.
If you celebrate the sabbats make a special meal with them or ask them if they would like to help with your altar or light your ritual candle if old enough.