got into photography properly at 13 when my forms "home room" became one of the science labs, and there was a darkroom adjoining. Before that, I had music lessons (specifically piano) from the age of 9... Never saw that as particularly "creative" as it was all either theory or technique and playing other peoples music not writing anything of my own.
Strangely, around 15, I was dragged into joining a band with a couple of my mates, we were all into the heavier side of rock, and i took up bass (and guitar to a certain extent) - and the music theory i'd absorbed suddenly started to spill out into writing all kinds of stuff - none of it brilliant imo - but i was the only one in the band writing music - guitarist added his own solos and wrote some lyrics. After college, and earning a bit more £££ i bought a couple of keyboards, but would still mainly play bass in the bands I was in. I think to be honest it almost needed a different instrument to "unlock" the creative bit of my mind because I'd been so focussed on the lessons and exams for Piano which were pretty much all "classical" based pieces.