Up until I was around 12, I listened to whatever was on the radio.
Around that time, by brother introduced me to some old slipknot which I loved. I wanted more, so I started listening to more metal. I listened to slipknot and pantera for a while....until I was like 13.
Then I got into DDR and for a while I would only listen to techno and j-pop (which I feel like a faggot for listening to now).
When I was 14 I bought guitar hero II I think and I started getting into older rock bands, but I still listened to mostly techno.
At age 15 I started getting back into metal, actually listening to death metal, thrash metal, etc. and exploring the genre more. I listened to metal and techno every once in a while.
Now (16) I listen to metal, techno, a little bit of punk, and (because I got into anime recently) anime intros.