What does being an EDM composer have to do with looking young? Would be more inclined to associate it with MDMA and other drugs that would wear the body down.
Look at Armin van Buuren, Darude, Jean Michel Jarre etc. For some reason there are many music producers/DJs in their 30s-60s that look way younger than they should ;-) I don't remember who was that but one DJ that was ~42 looked like 18 (non-asian) and everybody was freaking out (I'll try to find that pic somewhere). Maybe this type of music energy activates something in the brain, who knows?
Kind of a nitpick, but electronic != EDM.
I assumed that the meaning here was "people see the way I dress and assume I'm 15 years younger." I expect that anyone frequenting the EDM scene is dressing the part.