는 처음이야

it's my first time; I've never experienced something like this before

→ 는

phrase Rare #24,167

it's my first time; I've never experienced something like this before An informal pattern used after a noun or noun phrase ending in a vowel. The particle 는 marks the topic, and 처음이야 means “is the first time.” After a noun ending in a consonant, 은 is used instead, as in 음식은 처음이야.

KO: 이렇게 맛있는 요리는 처음이야.

EN: I've never had a dish this delicious before.

이렇게 거지 같은 날씨는 처음 이야

I've never seen such lousy weather before.

— 원스 어폰 어 타임 인… 할리우드 (2019)

초등학교 이후로 이런 섹스는 처음 이야

This is the first time I’ve had sex like this since elementary school.

— 파이트 클럽 (1999)