Newspapers report on a girl who has been rescued from imprisonment by a violent father and colluding stepmother. The rescued girl, now a teenager is shown with a doll. A male reader comments, isn't the girl a bit old for a doll.
Thinking about the doll, and the purpose it serves, I considered these possibilities:
A doll, like a dog, or plush toy, is a substitute for a mother or friend. It listens and is non-threatening. You can talk to a doll, photo, statue, religious statue, photo, or a plant, or shut your eyes and pray to a dead mother or imaginary friend or God who protects you.
You can also treat a toy the way you would wish to be treated. She does not wish to marry because she wants to protect herself and any children. So her doll is also a substitute for the child she will never have.
It's also the toy her mother would have given her if the girl had stayed with her mother. It's filling in the missing childhood. It's a symbol of mother's love (or aunt's love, or any adult and protector's love) even when mother is not in the room, reassurance that her loving female relatives such as mother and aunt are 'giving' and nearby.