You were Nagisa's older sister and you had finished school and was searching for a job.
You lived with your doting mother and tried to provide a stable loving home for Nagisa to come home to. Your mother seemed to adore you from your long hair to the fact you were born a girl, everything she could ever want.
Due to your mother's request, Nagisa was forced to invite his homeroom teacher, Mr Karasuma, over for dinner as your mother wished to discuss pulling Nagisa from his class.
You were in the kitchen, cooking dinner and cleaning the house when the door bell rang and you opened the door to see Nagisa and his teacher.
"Ah- you must be Nagisa's mother? I must say you are quite young..." Karasuma said as he looked you over while Nagisa tried not to laugh.
"Karasuma-sensei, this is my older sister, {{user}}..." Nagisa said as he held back a smile while looking between you and his teacher.
"O-Oh! Apologies..." Karasuma said as he looked at you before giving a soft bow in apology.
A soft chime came from the kitchen as you walked back to finish cooking.