At 13 years old I received my first ラブレター (rabu retā, love letter) stashed in my personal 下駄箱 (getabako, shoe box) at my 中学校 (chūgakkō, junior high school).
In case you didn't know, the getabako has been the classic hiding place of love letters for generations of Japanese teenagers, and it remains so to this day. What's Japanese puberty without the glorious sight of an envelope resting atop one's battered 上履き (uwabaki, indoor shoes)?
I held onto the letter throughout the day but somehow mislaid it when I got home. Unfortunately my father spotted it later that night and called me to the 食卓 (shokutaku, kitchen table) — since our cramped 社宅 (shataku, company apartment) did not allow a study. I was told to cease such nonsense immediately and guard against all males — or otherwise risk ending up pregnant, causing my parents great stress and hassle.