Ima no Tokoro wa, Otouto Miman.

I am about to turn 35 and one day I suddenly have a 23 year old brother. And he's going to live with me! There is no way that anything could happen, but--!
Since the death of her father, Azuma Azuchi had been living with her mother, as she pleased, but her mother announced that she was getting remarried. And the man she married and his son moved into the house! Even though they are suddenly asked to move in together, they are complete strangers. And he is a young boy! Awkward under one roof, Azuma decides to move out, and tries to make it work for the short time she has until then...
You never know what life has in store for you! Azuma decides to take a fresh look at her life, including her independence and marriage, but it doesn't seem to be that easy--!