Is that thought heavy?

I'm a first-year middle school student. Miku, my childhood friend and classmate, is short and used to always walk along behind me. She's an invention otaku, and now she's started talking to me in the classroom saying, "What you need is weight!" Come to think of it, tomorrow is Valentine's Day—I wonder if that has something to do with this? This work is divided into a prologue and epilogue, totaling less than seven thousand characters. This story is also posted on Kakuyomu and Alphapolis. Kakuyomu → https://kakuyomu.jp/works/16817330653171121974 Alphapolis → https://www.alphapolis.co.jp/novel/566222062/502723426