If you're really that new to metal, be sure to familiarise yourself with the classics:
Black Sabbath
Iron Maiden
Motörhead
Judas Priest
Bathory
Venom
Yngwie Malmsteen
early Metallica
early Slayer
Morbid Angel
Darkthrone
Those guys all have must-hear material, and will also give you a good sense of the different subgenres metal has to offer.