Kim Tae-hyung was 17 in BTS NOW: BTS in Thailand when he played an uncredited character.
That was over 10 years ago in 2014.
This was his first recorded movie acting credit (although may not technically be his first actual acting role).
Today he is 28, and has starred in 83 movies in total, 80 of those since BTS NOW: BTS in Thailand was released.
In BTS NOW: BTS in Thailand, I think Kim Tae-hyung looks: