This quote reflects Ellie's sense of vulnerability and insecurity. She feels like she is not in control of her own life and that it could be taken away from her at any moment. This is a common feeling among children, who are often aware of their own smallness and dependence on others.
The dandelion is a perfect symbol for Ellie's life. It is a beautiful and delicate flower, but it is also very fragile. A single puff of wind can blow it away, just as a single event can change the course of a person's life.
This quote also foreshadows the tragic event that will occur later in the novel. Ellie will die unexpectedly, leaving Jess and the other characters devastated. Her death will show them that life is indeed fragile and that it should not be taken for granted.