Well, my earliest memory related to that is when I was nine, in a first family visit to the Hayden Planetarium, my local planetarium here in New York City. The reason I say it was the first thoughts related to it is, at age nine, I'm not thinking career. As a kid, you just do what feels good. You do what you enjoy, and that first visit to the planetarium opened up a vista that I didn't know existed, especially as a native New Yorker.
We New Yorkers don't have relationships with the night sky. You look up, and there's a building there. When I grew up, there was much more light and air pollution. Yeah, you knew about the Sun and the Moon and maybe a couple of stars, but that was it, so it required this institution of a planetarium to take me to that frontier. And it would require another couple of years for that interest to be codified into a lifelong ambition to be not just a scientist but an astrophysicist, in particular.