Shouwaru Tensai Osananajimi to no Shoubu ni Makete Hatsu Taiken wo Zenbu Ubawareru Hanashi

Yoshizawa Wakaba's childhood friend, Umezono Komaki, is perfect.
She is a brilliant, well-behaved, honor student......, but beneath the surface, she is a vicious girl who looks down on others. I wanted to win over Komaki so badly that I tried to compete with her, even at the risk of losing "something important" - the result was my loss.
And so Komaki said, "Wakaba, kiss me," and she stole away my first kiss.
In order to regain my dignity, I challenge Komaki to another match, but she says that if she wins, she will take away another one of my most precious things.... Going on a date, sleeping in the same bed, even saying "I love you." I should have hated Komaki for taking all these first-times away from me, but what is this feeling that is filling my heart instead?
(Source: Sneaker Bunko, translated)
Note: Gold Prize winner in the 28th Sneaker Awards.