I'll keep it short; I started listening to metal music eleven years ago, back in 2006. I first received Nickelback's All the Wrong Reasons, then Guns N' Roses Appetite for Destruction from my mom. After that, things spiraled slowly and I was listening to Guns, then Metallica, then Def Leppard, then Megadeth, then Cacophony (I had also decided to start playing guitar), and many other bands. 

Please Help !
Thanks !

I didn't find the right solution from the internet.

References:
-http://www.metalstorm.net/forum/topic.php?topic_id=27484
-explainer videos

My father listened to Metal before I was born. 'Tis in my blood.

Since I was 7, so 22 years. Started with black metal \m/

I was being raised with metal music since I was 4,so for 19 years now  

I've been listening to metal since I was 13. It's 17 years already \m/

Since I was 11 so, 34 years :-)

well, since 1985.. my first record was live after death... maiden rules

11 or 12 yrs old, so bout 20 yrs

since the golden age of metal, 1983 ... it's 34 years of pure metal \m/

I've been listening to metal since I was 12 years old, sooo 11 years now