The Man in the Moon (1991) on Netflix

It's 1957 in rural Louisiana. The Trants are a loving family. Fourteen year old tomboy Dani Trant is the middle of three siblings. She is at the age where she has few responsibilities - although her father, Matthew Trant, believes it's time she did more around the house, especially as Dani's mother, Abby Trant, is pregnant again - and loves more than anything to go swimming in the pond in the empty neighboring Foster property, the Fosters who moved away fifteen years ago. She looks up to her sister, Maureen Trant, who she sees as the perfect, beautiful sibling, although Maureen, who will soon be heading off to college, readily admits that she has her doubts in life. As an example, she tells Dani that she may be dating Billy Sanders, but she is not going with him. When the now fatherless Fosters move back, Dani's life changes. Although their first few encounters are antagonistic, Dani eventually falls in love with the oldest Foster son, seventeen year old Court Foster, who now acts as the male head of the household following his father's death. Although there is some sexual tension between himself and Dani, he sees her more as a special friend. Regardless, Dani, who wants more than anything for Court to be the person who provides her with her first kiss, may get her wish. Their relationship may forever change when Court and Maureen eventually meet, they who are immediately attracted to each other. Both Court and Maureen are aware of Dani's feelings for him, so they have to decide what to do about their own romantic wants for each other.