The ceremony, the annual "Coming of Age Day" in Japan is a day where people who turned 20 the previous year celebrate becoming adults and often announce what they want to do in the near future with their life. For Naoya it was an obvious announcement and one that shocked nobody though should perhaps be taken as a sign of just how serious the "Monster" is in becoming the quickest Japanese fighter to win a world title.
Naoya, who turned 20 back on April 10th last year, has previously said he was wanting the WBA title, though it would seem likely, with all things considered, that he'd actual target one of the other 3 titles. Although a fight with WBA champion Kazuto Ioka would be major domestic news in Japan Inoue would be best advised to look towards one of the other 3 champions who would all make for easier foes.
Ranked by #4 by the WBA, #9 by the WBC and #12 by the WBO it'd be a genuine shock if Inoue didn't manage to fulfill his ambition of getting a world title fight this year.