Dekichatta kekkon (2001)

Hirosue Ryoko stars as Chiyo, 20, a department store clerk, whose first encounter with Ryunosuke, 30, a carefree bachelor friend of her sister's, leads to a pregnancy. Although of different worlds, they fell in love but Chiyo's father doesn't want these youngsters to get married. After eight months of struggles and growing up, they finally accepted each other as partner.