16 isn't too late for anything. Hell, 80 probably isn't. The 10,000 hours thing very much does apply to music, as the more you practice, the better you'll be, however... you shouldn't approach something with "mastery" in the front of your mind in the first place, so stop worrying about that and start playing some songs!

I've been singing for ~7 years now, since I was 14, and was surrounded by people who were far better than me, who I admired but was also jealous of. Young me would feel vindicated that I've kept on track for this long and now have some people following my example and taking me seriously, but current me has learned to let go of his ego and enjoy his craft, even as I finally close in on that golden number.