Isekai ni Kita kedo, Seikatsu Mahou shika Tsukaemasen: THE COMIC

One day Kaoru Aoyama is working as a normal office worker in Japan and the next she's waking up to find that she's become Patience Granger, the daughter of a viscount! She isn't sure if she's been reincarnated into this world or if she's just possessing this body, but one thing is for sure: This isn't a simple magical adventure in another world. Despite being nobles, the Granger family is destitute! Patience is desperate to figure out how to help her family, including her adorable younger brothers, but her magic proficiency lies in household magic—a type relating to domestic chores. Not only does she have her family to worry about but Patience is also ten years old. She'll be enrolling in the Royal Academy, where she'll have to navigate relationships with other nobles while trying to grow her skills. Using her knowledge from her past life and the memories she has from the original Patience, this young noble is determined to use her talents to protect her angelic little brothers!

(Source: J-Novel Club)