Birthday
Hanabi and Ayumu go shopping to get a present for Yuuto's birthday, after which Hanabi will go on a date with Yuuto and give him his present. Ayumu purposefully makes her late for the date, and tries to tell her that he likes her, but is interrupted by Yuuto. Due to a misunderstanding, Hanabi ends up thinking that Ayumu hates her, which depresses her, because she had grown to want to be his friend.
Aired 02/05/2016EP 5 - Birthday

12-sai.: Chiccha na Mune no Tokimeki
The story begins with Hanabi, a sixth-grade girl who is neither an adult nor a child. She deals with issues such as accidentally witnessing her homeroom teacher kissing, and worrying about experiencing physiological changes before her friends. This is the depiction of a 12-year-old girl's innocent worries and first love.
(Source: Anime News Network)