Perhaps it's a story about a single character and their journey, with the people they meet along the way being important secondary characters. The main character could be someone who has had a life - changing experience that will be 'forever in my heart', and the other characters help shape that experience.
It could be about loss and remembrance. The title gives the impression that there is something or someone that is held dear in the heart forever, perhaps because they are no longer present. So it might explore how a character copes with that loss and keeps the memories alive.
"The heart is always young" was a common phrase in novels. It usually appeared in youth romance novels or martial arts novels. It meant that the protagonist still maintained the beauty and innocence of his youth deep in his heart. Even as time passed, he could still maintain his kindness and love for himself and others. The meaning of this sentence could be compared to a person leaving behind beautiful experiences and memories at a certain stage of his life. These memories would always accompany him/her, and even at the end of his/her life, he/she would never forget his/her former glory and beauty.
It could be about characters who retain a child - like essence throughout a fictional story. Maybe it focuses on their innocence, sense of wonder, or their ability to see the world in a simple and positive way that is often associated with children, even as they grow or face complex situations in the fanfic's plot.
It's possible. A story can potentially last forever if it has elements that remain relevant and engaging over time, and if it keeps evolving and resonating with readers.
Some people are just nervous when they are telling a story, especially if they are in front of an audience. This nervousness can make them slow down, repeat themselves, or add unnecessary explanations to make sure they are being understood. They might also be constantly second - guessing what they are about to say, which all adds up to taking forever to tell the story.
I'm not sure as I haven't read the novel specifically. But usually, there would be a male and a female lead whose relationship is the focus of the story.