The significance of the book title is to, encourage readers to keep their head up no matter what.
Step-by-step explanation:
The author could have chose this over anything else because it has the most similarity with what the book is about. Titles are meant to give you a clue as to what the book will be about. Most of the time if you pick up a book and it says "the lost pokemon" that's what the book would be about. Some titles have a deeper meaning like "twilight" see we know the book isn't about the sky but has a deeper meaning about the beauty of a situation.