The relationship would change because Naruto and Itachi being the same age would mean they are more like peers in Sasuke's eyes. Itachi wouldn't have the same air of mystery and superiority that he had in the original story. Naruto and Itachi could work together to help Sasuke deal with his family's past and his own insecurities, creating a more positive and collaborative dynamic within the three of them.
Their relationship with Sasuke would be very different. Naruto might not look up to Itachi as much as in the original story, and Itachi might not see Naruto as a potential threat to Sasuke's growth. Instead, they could both be like older brothers to Sasuke, guiding him in different ways.
Since Naruto and Itachi are the same age, they might form a trio with Sasuke earlier. Itachi could teach both Naruto and Sasuke some of his skills without the age - based hierarchy. This would strengthen the bond between the three of them, and Sasuke might not feel as much envy towards Naruto as he did in the original story.
Their relationship would likely become more of a friendly rivalry. Since they are the same age, they would constantly be comparing their progress in ninjutsu and other skills. Naruto would probably be more eager to prove himself against Itachi, and Itachi might see Naruto as an interesting opponent.
The story would be transformed in many ways. Naruto, being as old as Itachi, would have had different training experiences. He might have been trained by different people or in different ways. This would lead to different jutsu and abilities. In the political arena, Naruto could have played a more active role in preventing the Uchiha - Leaf Village rift. His relationship with characters like Kakashi and Jiraiya would also be different. For instance, he might have been more of an equal to Kakashi, and Jiraiya might have had different expectations of him. All these changes would create a whole new narrative for the Naruto story.
Naruto's relationship with Sasuke would likely have a new layer of respect. Naruto, having been trained by Itachi, would understand the Uchiha clan more, which is a big part of Sasuke's identity. This could make Sasuke see Naruto in a different light too. Instead of just seeing him as a rival, he might start to view Naruto as someone who is also connected to his family in a way. They could start to communicate better, with Naruto being able to speak more knowledgeably about Sasuke's family and their history.
If Naruto was the same age as Itachi, their relationship could be complex. They might start as rivals, both being extremely talented in their own ways. Naruto's boisterous and determined nature could contrast with Itachi's more reserved and burdened self. Itachi might see in Naruto a different path for the Uchiha, one that doesn't involve the darkness he has known. Naruto, on the other hand, would probably be in awe of Itachi's power and at the same time try to understand his seemingly cold exterior.
In this fanfiction scenario, Minato would not have the same kind of paternal - like relationship with Naruto. Instead, they could be rivals in love for Kushina's affection. Minato would also have to prove himself not just to Kushina but also to Naruto. Their relationships would be a web of competition, friendship and budding romances. It would be a completely different story from the original, with different power dynamics and emotional entanglements among the three characters.
Naruto's relationship with Jiraiya would be different. Instead of being his student in the traditional sense, they might be more like peers. Jiraiya would probably still see Naruto's potential but would also be training Minato at the same time. So, Naruto would have to compete for Jiraiya's attention. With the other Konoha ninjas, Naruto being the same age as Minato would make him a more respected figure right from the start. He'd be seen as part of Minato's generation and might be involved in more high - level missions earlier.
With Sasuke, Naruto's rivalry could take on a new dimension. Anko might be in the middle of their dynamic, trying to keep the peace or even fueling the competition in a different way. Maybe she would see potential in both of them and try to push them to be better in different ways, which could either bring Sasuke and Naruto closer or make their rivalry even more intense.
Naruto's relationship with Iruka might change. Since Kurenai is now the same age as Naruto, Iruka might see Naruto in a different light as he's interacting more with Kurenai. Also, Kurenai's relationship with Asuma could be different. Maybe there would be less of a mentor - student vibe and more of a friendly competition among the four of them.
If Naruto was born the same age as Itachi, the story would be drastically different. Naruto would be more mature and skilled earlier. He might have been involved in the Uchiha massacre situation. Maybe he could have even tried to prevent it, given his nature of not wanting to see people suffer. This would also change his relationship with Sasuke. Instead of being an older peer, he would be more of an equal in age, and their rivalry could take on a different dynamic, perhaps more of a mutual understanding from the start.
Their relationship would likely become more complex. They might start to protect each other more fiercely. For example, Sasuke might not leave the village in the first place because he now has a closer family tie to Naruto. Naruto would also be more insistent on getting Sasuke to stay and see him as an important part of his family.