I'm 30, so on the edge of what you're looking for. When I was 12-14 I was into Nirvana and Nietzsche, X-Files, Star Trek TNG (might've been in reruns), my pet iguanas, cats, and rabbits, and catching crawdads in the creek. I read Clive Barker, William Gibson, Kurt Vonnegut, Anne Rice, Kathe Koja, Poppy Z. Brite, Stephen King, Heinlein, Asimov, etc. Lots of horror and science fiction. Plus I liked to read Freud and Jung, and medical reference books. I loved Neil Gaiman's Sandman stuff. I also read Spawn comics, The Maxx, Bone, and JTHM. I was just getting into sculpture and painting, and my room was full of half-finished projects. I was a cutter, and I filled notebooks with whiny writings. My walls were covered mostly with pictures of plants and animals. I rode my bike a lot.
Come to think of it, I'm probably the wrong one to ask. I wasn't normal. I read the bible a lot because I was losing my faith and trying to be sure of how I felt about it. I was into vandalism and petty thievery. I didn't have stable housing or consistent adult caregivers at that age. I wasn't usually in school, so I collected textbooks from thrift stores and studied them. I made charms out of feathers. I started taking entheogens at 13 or 14.
Lol yeah I was a messed up kid. I'll post this anyway, but I don't think it's representative.