I have a younger brother myself, maybe that's why I found this movie so special and so touching.
You told your story in a very silent, peaceful way, a good choice for such a movie imo. At first I thought it was just about the race itself. The way how you let the story arc develop was simply great, besides your animation skills you are also a talented storyteller!
Too bad you didn't enter NATA, I hope you will do that next year. Your 5 months spend on this project are well spend, I'm rather sure you will look back on this movie with (well-deserved) pride.