Judy begun as a bunny who was determined to be a cop even though no one thought she can do it because bunnies weren’t supposed to do anything except be carrot farmers. When she gets to Zootopia the other police think she is a token bunny and not a real cop. Judy doubts that she will ever make it. I think that her determination to keep trying even though she keeps failing will help her keep going.
Judy shows she has changed when she returns to Zootopia. She used to think the world was perfect and that she had to be perfect too. Then she realised that " real life is messy" and everybody makes mistakes. She knows that if everybody keeps on trying things will get better.
Judy changes from self-doubting to a belief that everybody can make mistakes and still succeed and you just have to keep on trying.
