25 years ago - Dolphin is born.
23 years ago - 2-year-old Dolphin is lost at sea. She is saved from drowning by an alien race that begins mutating her.
13 years ago - 12-year-old Dolphin escapes from the alien labs after they abandon their experiments.
10 years ago - 15-year-old Dolphin is found by a merchant sailing ship, where she gets her name and learns sign language.
8 years ago - 17-year-old Dolphin retreats back into the ocean to explore.
6 years ago - 19-year-old Dolphin meets Aquaman & helps him on his quest to save his son. She brings them back to Atlantis when he loses his hand, and once there, she meets Garth.
olivernome on deviantart
Dolphin is an incredibly tricky character to get right, because outside of her original appearance she's been used almost exclusively as an ornament in the stories of the men around her. Originally, she was a very simple but likeable character created in the pages of Showcase by jay Scott Pike, a girl that had been adapted by alien abductors for life in the deep ocean, and who had adventures interacting with surface dwellers and ocean life. She lived very much like an actual Dolphin, with all the wide-eyed wonder and soulful wisdom that implies.
It was many years later when she became a love interest for Aquaman. This version of Dolphin was written and drawn in a way that seemed to needlessly sexualize her, making the inevitable conflict between her and the returned Mera seem unnecessarily campy. Of course, later on, she would have a relationship with Garth and become his wife and the mother of his child, but then she was quickly being written as a demanding partner, constantly demanding his attention while her served alongside the reformed Titans.
Frankly, none of this is necessary. There's no reason for Dolphin to become romantic with Arthur, especially since he's on a quest to save his son. She's a better character, and more in keeping with the original concept, if she helps him simply as a friend. Likewise, her relationship with Garth doesn't have to become antagonistic. Frankly, the idea of seeing Dolphin as a mother is immediately adorable. If their relationship were written correctly, then it wouldn't be about Dolphin hounding Garth to come home, it would be about the three of them constantly trying to spend time together.
It's worth pointing out that while Garth and Dolphin's child is canonically a boy named Cerdian, we instead made it a girl named Mareena. The Aquagirl character in the Batman Beyond series is Mareena, Aquaman's daughter, but she could easily be the daughter of Garth and Dolphin instead, and would be just about the same age as Roy's daughter Lian and Wally's daughter Iris.