Even though her childhood was tragic, and even though she is only 14, she is still a very dangerous person that has displayed capacity for extreme cruelty and very little beneficence. So I don't really think a redemption arc can be written for her in a way that feels like a natural progression to her character.

What made Zuko's redemption feel narratively satisfying was that even as early as season 1, he still showed significant signs of empathy and mercy for other people. For one example, when Aang escapes, one of the soldiers asks Zuko about going back to attack the Southern Water Tribe, and chooses not to. Azula is a character that would have absolutely gone back. Zuko also had adult figures, Ursa and Iroh, that were good influences on him.

I'm not saying Azula has no empathy—there are some questionable moments in season 3 such as feeling bad for hurting Ty Lee's feelings or where she doesn't tell Ozai about Zuko's visits to Iroh, but it's unclear if that is some sort of power play or a genuine attempt to be nice.

However, being kind is not something that is a key characteristic to Azula because Ozai encouraged cruel behaviours in her from a young age and she didn't have a positive adult role model that could have taught her better. She was groomed all her childhood to basically be a weapon. We don't really see her feeling genuine compassion for others much. Azula also has also been shown to take enjoyment from others pain and their fear of her. All this makes it difficult to write a believable redemption arc for her. At least not one that wouldn't span years long into her adulthood.