Never understood why people thought Kishi would do a callback to chapter 3....it happened 15 years ago and was never mentioned or hinted at again.
It doesn't matter when it happen in term of years. The thing that matters is that it happened in the beginning of the story when we were introduced to the characters, the universe, the rules, what motivates these characters, their goals. etc.
And when you start a story that's about a journey you also have to finish that journey, to come full circle with it so to say.
Naruto wanting to become Hokage and his love for Sakura were two of the things we were introduced to. And his love for Sakura also included the forehead comment.
Sakura hated her forehead, Naruto was the only one that liked the one thing that she didn't like about herself. Later on in the story this was referenced indirectly through Minato and Kushina.
Kushina hated her hair, Minato was the only one that liked the one thing that she didn't like about herself. Connecting this moment to the main protagonist and heroine of the story. Naruto and Sakura.
Of course all of this is null and void due to the ending. Where the main protagonist was reveal to have been Sasuke all along, and we were too stupid to see this, and not only that he stole the spot from Naruto but he also stole that moment (not in the exact way but still stole it). While the heroine of the story was Hinata the side character.
So in reality we followed what was told to us for 15 years only to be reveal in the last second that all of it was for nothing. Because nothing that has ever been said in the story thus far mattered in the end. Nothing. It's all pointless.