I'm 58. My discovery of Black Sabbath at age 12 changed my world. I followed them till Ozzy left. In the late 1970s, I listened more to King Crimson, who I didn't learn of till around age 17. Bands not considered metal included Alice Cooper, Genesis (preferred Gabriel era), Yes, Emerson Lake and Palmer. Also early Blue Oyster Cult, Led Zeppelin, early Queen, and Rush. In the 1980s, I was listening to the new era King Crimson, Frank Zappa. Bill Bruford, Alan Holdsworth, The Cure, Big Black, Peter Gabriel (up to SO), and was exploring Jazz and Classical. No 80s metal whatsoever. In the 1990s, it was John Zorn (including Naked City and Painkiller projects), Ken Vandermark, Joe Satriani, Steve Vai, Metallica (from Black album to earlier), Testament, Sepultura, Malmsteen, Soundgarden, Alice in Chains, Tool, also more Jazz, Classical, Country, old Cowboy songs, and old Celtic songs.
Then I discovered Pantera (Vulgar Display of Power). Then Lamb of God. The next significant discovery was Opeth (Blackwater Park) about five years ago. In Jazz, it was John Coltrane and Free Jazz sometime in the late 1990s. Opeth was very important, and I began exploring through YouTube what had been happening in Metal since Pantera. Favorites, some not strictly Metal, I've found include: About Tess, Agalloch, Altar of Plagues, Amia Venera Landscape, Circle of Contempt, Cloudkicker, Don Caballero, Dream Theater, Gojira, Gru, Isis, Liquid Tension Experiment, Meshuggah, Neurosis, Russian Circles, Type O Negative, Zu. Of those, I listen most often to Agalloch, Cloudkicker, Meshuggah, and Zu. If you like John Zorn, check out Zu (Ken Vandermark is in it) and late John Coltrane.