Isekai Ouji no Toshiue Cinderella  

Cinderella of the Prince in Another World, 異世界王子の年上シンデレラ

One day, Rika was unexpectedly transported to another realm where she was chosen as the bride of a young prince who is only 11 years old. Despite her initial discontent, Rika gradually grew fond of the prince and his love for her. As she searched for a way back to her own world, Rika decided to care for the prince's growth with a nurturing attitude. Thus, her life with him began.