L'Attache coeurs (2006)

Blurb:
Legend says that fated lovers are bound together by an invisible red thread. Most people think it’s superstition, but seventeen-year-old Chiyako knows better -- she can see them! Yearning to be an independent adult, she’s struggling to earn enough money to move out of her parents' house. Her path is clear, until a chance encounter with a mysterious group of hot guys known as the Tyers shows her that she has the power to pull all of fate’s strings...though doing so binds her into the form of a child!

Source: www.anisearch.com/manga/1127