Harry Potter died to protect everyone, but only one person was on his mind when he did: Ginny. Indeed, Ginny was the very last person Harry thought of before he sacrificed himself. As J.K. Rowling wrote, "Harry thought inexplicably of Ginny, and her blazing look, and the feel of her lips on his–" Is it coincidence that out of everyone who was fighting alongside him, in that moment Harry could only think of the girl he loved?
When Voldemort tried to burn Neville alive, we saw that his spells simply wouldn't hold on the fighters of Hogwarts. But we also know how complicated sacrificial magic and love magic were in the world of Harry Potter. It would not be surprising to us if Harry thinking of Ginny in that moment somehow meant that his protection of her specifically was amplified, giving her a special and increased protection against Voldemort that no one else had.