high schooly

Pronunciation: \ˈhī ˈskül-ē\
Etymology: English (high school) + Nick (-y)
Date: 2010
...
1: acting or portraying someone young in secondary school <childish>
2a: exhibiting less than an expected degree of maturity <immature>
2b: having room to grow into a conventional or post conventional moral reasoning <foolish>

it was really immature and high schooly