未成年未长大 Underage Yet To Grow Up – Conveys the idea of being underage

Relation Nicknames

未成年未成熟 [wèi chéng nián wèi chéng shú]
Underage and immature Perhaps used ironically indicating the person acknowledges immaturity ...
还没长大 [hái méi zhăng dà]
Not Grown Up Yet This signifies an ongoing journey towards maturity often with a hint of reluctance ...
我叫未成年 [wŏ jiào wèi chéng nián]
Literally means I am underage possibly expressing youthfulness lack of maturity or even innocence ...