If you want Jas to live with you, these are the current, community-approved methods: Adoption Mod (The "Ethical" Alternative)
Download the Stardew Modding API, which serves as the foundation for almost all Stardew Valley mods.
To help find the exact visual style or framework for your playthrough, let me know:
Stardew Valley’s modding community is legendary for expanding the limits of Pelican Town, allowing players to alter everything from farm aesthetics to complex character relationships. Among the many character-focused modifications, players often search for ways to expand interactions with the younger residents of the valley. However, when it comes to the specific search term it is crucial to address the community's boundaries, the technical reality of the game's code, and the best alternative mods available to enhance your gameplay experience.
: While a single "perfect" mod for this is rare, players often combine the Free Love mod with custom roommate scripts to let Jas move into the farmhouse as a "roommate" (representing a daughter).