I think I started explaining introvert/extrovert and the concept of needing to recharge when A was around age seven
and she really seemed to grasp it around age nine. Now,I can just tell her that I'm feeling drained or "I need quiet so I can be inside my own head." And she stops talking for awhile.
Reading is a great way for me to connect with my kids,be around them and they can hear my voice. What Katigre's said