In the computing world, at least on Microsoft products, the “undo” function is accessed by the CTRL-Z key combination. Undo is a powerful concept; one that unfortunately doesn’t exist in the real world.
The difference between bringing my cat home and not bringing her home is permanence. Once I make the choice not to assume responsibility for her treatment and care I can never undo that choice. I have to live with the consequences from that moment forward.
Bringing her home gives me time to see what it is like to care for her. Whether that situation lasts for a day, or a week, or a month, or years - it isn’t permanent. When (if) the responsibility of caring for her exceeds my ability and desire, then I can make the permanent choice.
Being an adult sucks sometimes.