This is always a weird question for me to answer, because I don’t actually remember a time before I was into the characters, particularly Batman. I think my initial exposure might’ve been the Scooby-Doo episodes that crossed over with Batman, but it could also have been the Adam West show or the animated Justice League series. I saw them all when I was so young that the exact order and timing is a little murky for me.
For reading comic books themselves, though, that’s a lot easier to answer. I’ve always been interested in the comic continuity, and I’ve read a lot about it and watched reviews and such, but for a very long time I wasn’t sure what books I would want to buy because getting everything I was interested in would’ve been too expensive. I’d read a few scattered Batman books (I think my first was a collection of classic Batman stories from the '50s), but that was about it.
Then I subscribed here back in October sometime and I’ve been reading pretty much nonstop since then.
I can also say more easily how I got into Marvel. Growing up as a DC fan, I thought of Marvel strictly as the enemy, until my mom finally talked me into watching the first Captain America movie. That hooked me, though I still haven’t read any actual Marvel comics (same indecision-paralysis as with DC, except I’m not as interested in Marvel Unlimited).