Kodomo no Kodomo(2005)

Kodomo no Kodomo

A playful 11-year-old girl named Haruna has been friends with a quiet boy named Hiroyuki for years. After entering the fifth grade, the two meet one spring day at the park where they have always played together. However, the unexpected occurs, and Haruna later realizes after a sex education class that she has become pregnant.

(Source: Anime News Network)