A plus - size model with big breasts could be the main character. She has a journey in the fashion world, facing both rejection from some traditional agencies but also finding new opportunities in the body - positive fashion movement. She uses her platform to promote self - love and acceptance for all body types, not just those with big breasts.
A young girl going through puberty could be the main character. As she starts to develop big breasts, she faces teasing at school but eventually finds a group of friends who accept her for who she is.
It could also be a wet nurse. In some cultures or historical contexts, a wet nurse is a woman who breastfeeds another woman's child. So in the story, if it is set in such a context, the wet nurse could be the main character, with her own story of why she is in this role and how it affects her life.
It could be Daenerys Targaryen. She's already a strong and unique character. If she were to be the main character in such a story, the breast expansion could be part of a new magical transformation she undergoes as she continues her journey to claim the Iron Throne. It could add an interesting layer to her character, as she already has the power of her dragons and this new physical change might make her even more of a figure to be reckoned with in the eyes of her followers and enemies alike.
It could be a patient who is battling breast cancer.
A single mother who is trying to raise her children while working multiple jobs in the big city.
It could be a young adventurer, full of curiosity and courage, like a teenage boy or girl who is eager to explore the world.
The main character is obviously the man who owns the big garden.
An inventor could be the main character. While working on an experiment to create a new type of super - food that provides a huge amount of energy, he accidentally consumes some of it. This causes his belly to start expanding uncontrollably. He then has to use his inventive skills to find a way to reverse the effect while also dealing with the practical problems of having a large belly, like getting around his cluttered laboratory.
A little girl with unusually big feet for her age. She might be self - conscious about her feet at first. But in the story, when she enters a fantasy realm, her big feet become an advantage. Maybe there are little critters in this realm that love to tickle big feet, and she has to work with them to save the realm from a dark force.
Maybe it's an alien being who has a different body structure and the 'big boobs grow giant' is a normal part of their growth cycle on Earth. This would make the story about how they adapt to Earth while also dealing with this growth and how humans react to it.
Based on the title, the main character is likely the boy. But we don't know much about him yet.