It's really embarrassing when the eighth-grader syndrome kicks in.
Tips
culture
中二病 comes from the Japanese 中二病 (chuunibyou), literally 'second year of middle school sickness.' It describes the phase when teens believe they have special powers, a dark secret identity, or see the world differently from 'normal people.' Popularized by anime.
usage
Used to tease someone acting melodramatic or self-important. 中二 alone works as an adjective: 你也太中二了 (you're so cringey/delusional). 中二病发作 = having a chuunibyou episode.