He took another bite, and this time talked around it so he could continue chewing. "Decade and some change." He'd started when most people were graduating high school, and now years later he was still alive. He swallowed his bite of the pizza before continuing. "I only knew about vampires at first. But I kept looking and found more and more." He didn't get into why he'd done it. She hadn't asked, and he didn't want to give her some long speech about his everpresent guilt complex unless she asked about it.
"You do it for as long as I have, you pick stuff up." He shrugged. "I've got plenty of assorted bits of trivia up here." He tapped his head with his free hand. "And I could tell you three or four different people, just off the top of my head, that would know something I don't. That's one of the biggest advantages those of us that don't have kickass superpowers have over the bad guys. We've got a huge information network." He chuckled a little and added, "And I've got a pretty good memory. That helps, too."