I'm sure everyone has their own list of TV programs, books, films etc. that influenced them when growing up. One of mine was Carl Sagan's Cosmos and I was 14 when it was first shown. That's a pretty influential age for any child, but especially one whose head was already in all things science (fiction and fact). My memories of that time often have a Cosmos link, whether it's walking along the beach contemplating that they are more stars in the universe than grains of sand on all of the beaches in the world or where we would be if Library of Alexandria hadn't been destroyed.
I can trace many of the things I did in my career back to Cosmos, including taking astrophysics at University and continuing to consider myself a scientist no matter what I do. However, apart from the first ever screeing of the program and maybe a repeat early on, I haven't seen it for well over twenty years. I've got the book and pretty much every other book he wrote, but I always longed to see the program again. So when it became available on DVD I snapped it up, and recently began to watch it again. Well time certainly hasn't diminished it's power and relevance; I'm finding it just as compelling a watch as I did almost thirty years ago. If you haven't seen it before, or it's been many years since you did watch it, I can thoroughly recommend another viewing: you won't be disappointed and maybe it'll instill a sense of wonder at the universe in to you, as it did (and does) with me.