Kodomo Janaikara Hayaku Shitai

Sana has had a crush on her childhood friend, Kyosuke, who lived next door and was seven years older. She loved how Kyosuke always played with her when she was shy and couldn't make friends, so she went to the same university and joined the same company as him. She was enthusiastic, saying, "I have had this crush for 11 years, and I'll make it happen this year!!" But even though he said he wasn't popular, Kyosuke was always surrounded by other girls at work, so she decided she had to make a physical move first...!?

(Source: Bunkasha, translated)