'Our daughter' would be «на́ша до́чь» or (less formally) «на́ша до́чка».
A girl you trained at sports as a coach, for instance. A teacher could say that being proud of his/her student.
Basically, any girl you are somehow associated with.
In English, I can say "our girl" and pretty much everyone would take that to mean "our daughter." So I take it that's not the case in Russian?