своя комната

one's own room

→ свой
phrase Very common #1,796
one's own room Своя is a possessive form meaning “one's own”; it changes form to agree with комната and its role in the sentence.
RU: У каждого ребёнка должна быть своя комната.
EN: Every child should have their own room.

Теперь у Тома есть своя комната.

Now Tom has his own room.

У него своя комната.

He has his own room.

Дома у меня своя комната.

I have my own room at home.

У меня будет своя комната?

Will I have my own room?

— Мамочка (2014)