Kannushi-san to Boku no Kanojo

Isako, the only child of the family running the Arita Shrine, suddenly finds herself living with her childhood friend Haruka Kumoi, who is a potential heir to the shrine. Isako is confused by the overprotective Kumoi, but as she spends time with Kumoi, who knows her so well, she grows up and learns to face her true feelings... This is the first full-fledged shoujo manga by Fumi Fumiko!

(Source: Margaret Comics, translated)

Note: Chapter count includes one bonus chapter.