Split Infinity (1992)

Although 14-year-old "fashion plate" and entrepreneur A.J. Knowlton loves her down-to-earth, middle-class family, her behavior toward them often reflects irritation and embarrassment. She blames her grandfather for losing the family farm during the depression and keeping the family from becoming affluent. One night when A.J. goes to the barn to be alone, she falls from the hayloft, then awakens suddenly to find herself transported back to the year 1929. Her grandfather is a young man and she is his little sister, Amelia Jene. Before A.J. returns to 1992, she will gain a new set of values as she discovers the loving secret her grandfather has kept for so many years, until the day she would be ready to understand.