So, at the end of the game, Zelda makes Link return to his childhood for good to relive the seven years he lost after Ganon was defeated. But why couldn't that cold, idiotic Zelda just leave Link as an adult? She just messed up the whole timeline.
She thought she was doing the right thing 7 years ago, making Link collect the keys to the temple of time, but really it ended up with Ganon taking over the Triforce of Power. After they defeat future Ganon, she sent him back in time armed with the knowledge he, by the end of the game, has to stop the Ganon from 7 years ago from ever obtaining the Triforce of Power; and maybe she wasn't aware about the consequences to the flow of time this would have.
If you paid attention you notice Zelda was anything but cold and idiotic. First of all Zelda wanted Link to enjoy his childhood because that was taken away from him. And Zelda either knew Link would be able to keep his memories and warn Hyrule in time and trusted him. I get that you dislike Zelda but hey it wasn't Zelda that messed up the timeline. It was Nintendo.
Once again it isn't "stupid cold Zelda" Zelda wanted to give Link back the time that he lost, and when you see child Link show up as a kid again i take it as him warning Zelda of what was to come, thus foiling Ganondorf's plans.
Zelda sent Link back in time in order for him to properly live the childhood years that were stolen from him. She was giving him a chance to see what Hyrule could have been had the problem with Ganondorf been solved before he ever entered the sacred realm. She didn't know there would be unfortunate consequences with sending the hero back in time and thus leaving post-Ganon Hyrule without a hero because, as far as she knew, the threat was gone and they no longer needed Link.
I haven't played the whole thing but from the little bit I played of it, it seems really good. I heard of how dark the game was, though. Link doesn't deserve to go through such dark experiences especially at that young age.