My son got interested in Astronomy at the age of 4 owing to a British series on the Discovery Channel. It was called Amazing Space in the US, and was narrated by the actor who plays Spock's father in the old Star Trek. Originally it was called Encyclopedia Galactica in Britain.
My wife, who was resting as she often did in the afternoons on the weekends, made fun of me for putting it on, all 12 hours of it on 2 video tapes to keep him amused while she rested and I headed off to work. She woke up nearly 4 hours later and he was still watching, and like kids do, he absorbed it all and could talk quite knowledgeably. Two years later I took him to the Dunlap Observatory, established in the 1920's about 15 miles north of Toronto, before light pollution became a problem. The astronomer, a PhD who gave the lecture was very surprised by his knowledge.
Sadly, he drifted away from it in adolescence though he watched Patrick Moore with me, and told a story about him to Canada's premier amateur astronomer who was visiting a telescope shop near where we were living when we returned to Toronto which cracked him up.
I still like astronomy.