Takiko's life is hard and always has been. She is the child of a drunk, violent and abusive father and a passive-aggressive mother living in squalor and poverty. For her this is a fact of life against which she doesn't rebel. She accepts the repeated sight of her bruised face as the inevitable aftermath of her altercations with her father, she accepts his drunken shouting, her own high pitched cries, her mother's constant weeping, and her younger brother's impunity from it all. Her pregnancy and subsequent motherhood force her to continue living with her family in their miserably unhappy home, with no hope of being able to leave.
Twenty one year old Takiko manifests as a narcissistic, barely socialized young woman, drifting from one joyless casual relationship to another, never developing any feelings for any of these men she casually encounters, nor for that matter for any human being with whom she interacts. She seems to be emotionally stunted, and all her relationships are cold and meaningless. That has been her life.
Her decision to give birth to her son and keep him despite the continuous urgings of her family to give him up and the difficulty of raising him on her own is, I believe, supposed to mark a change in Takiko. Indeed, for the first time in her life she is invested in another human being. She loves her child and cares for him as best she can.
But my take on it (and from reviews I've read I know that I'm in the minority), is that her decision to go through with her unplanned pregnancy is an extension of her narcissism rather than a selfless decision favoring the unborn child. As she herself admits, the pregnancy seems to have nothing to do with her. She can't even refer to the being she is carrying as a baby. He is "the fetus". Takiko has no qualms about bringing the baby into her dysfunctional family home, disrupting their already chaotic existence, living at their expense and feeling no empathy for her mother who is working her fingers to the bone to make ends meet.
When she begins to work in the (garden) nursery, she is infatuated by the quiet and serious Kambayashi, a man whose challenges are as difficult as hers, if not more so, but whose outlook on life is so very different from hers. Their friendship, like the birth of her child, seems like a potential turning point.
In Kambayashi she finally meets a character with values, with true inner strength, with a generous, altruistic and optimistic outlook on life. Kambayashi is the complete opposite of Takiko in every respect.
Perhaps her exposure to this man will change the vector of her life and, combined with her true and sincere love for her son, set her on a different path.