That means he has 1 more left until he reaches his own young adult age.
Which means that, he turns 18 years old next year in November 4th 2024 which he will graduate by finishing school in June 2025.
I know that @HenryTheVietnameseAmerican07 is now 16 years old or 16, since he turns one on Wednesday in 4 days since he will finish school by June 2026.
MAG.MOE - The MAG, The MOE.