I've met two deeply talented software engineering minds in my life, and they fall on opposite ends of the spectrum: The first I met when I was in my mid-20s and he was about 17. Gifted kid, absolutely. He'd published a programming book (!) and could do things with JavaScript that, in 2001, nobody had even thought of doing until the mid 2010s. Totally undisciplined of course -- we hired him and he refused to follow an…
Of course it's for different reasons. Something many people don't want to admit is that a lot of talent comes from practice and experience, and someone in their 40s is much more likely to have 20+ years of experience than someone in their 20s.
The early-20s geniuses I know are talented for different reasons. The ones I am thinking about are people who pick up new things absurdly quickly; pick up on patterns very easily; have general experience in enough domains to make quick connections; etc. But some of them are extremely undisciplined (which may or may not be related).
Those same people with age, gain not only experience but also hopefully discipline. A combo like that yields you people like John Carmack and the like: Not just talented, but out-of-this-world "next level".