I was definitely interested in pee well before I hit puberty. Hearing about girls peeing caught my attention cause I didn’t know that much about their anatomy, so I was curious about it.
My sisters had those teen-girl magazines, so when they weren’t around I would read the part of the section of the magazine where girls would write in with embarrassing stories, because every so often one would be pee related. (This was still pre-puberty, so I didn’t whack it but I would still get excited reading about it.)