OP - I turned 46 last week. I grew up on classic Dio, Priest, Maiden, Accept, VH, Sabbath and AC-DC with Bon Scott. I love that stuff. It's on constant rotation on my MP3 player. However my listening pleasure has grown with age. I listen to 70's funk, Prince, Mike Stern, Johnny Winter, Frank Marino, Electric and acoustic blues. It's a heady mix of genres.
I don't play metal anymore. Not because I can't or I worry about my image. I play what I hear in my head. These days its stuff like Johnny Winter, Frank Marino and Eric Clapton. I actually used to worry that my metal friends would think I sold out. LOL!!
Play what you love. The rest will fall in place.
Though I'm ~9 years younger, my early experiences are pretty much the same as yours (I have four older brothers who helped shape my early musical tastes... thankfully). However, I broadened my musical horizons early on by picking up the trumpet. That got me into a lot of jazz, blues, and classical music that I otherwise wouldn't have listened to. Lately, I've even been getting into chicken pickin' country stuff.
I play all sorts of music, but I still play metal as well m/... the riffs from "The Hellion" into "Electric Eye" get my blood pumping every time.
As for growing old gracefully, here are some of my gigging guitars:
I regularly play all of these (minus the red mini-v... that belongs to my kid) in my classic rock cover band & the audience LOVES it! Why the hell would I want to 'grow up'?!?!