Not much is known about Trini before being a Digi-Ranger, save the facts she's a master a kung-fu and her best friend is Sonia.
Trini becomes the Yellow Digi-Ranger, with Agumon as her partner. She wasn't confident her ability as a Ranger, but Agumon advised her and made her more self-confident.
"Dark Digi-Ranger" arc
When Dan's twin brother Ian, came to town many thought they were the same person. The only real difference is voice and clothing. Trini was all the more curious to the identity of the Silver Digi-Ranger. When she found out it was Ian, she tried to make sure Dan would be okay.
When Ian and the others found out about Ian's Digi-Armor's power being drained, Dan tried hard to save his powers, but he ran out of time and most of the Silver Power left Ian. Trini and Agumon never said anything about this.
When Bagramon came he created a new world in-between the Earth and Digital World, called the DigiQuartz. The Digimon gained new powers, and the team began jobs as Digi-Rangers Hunters. They were given a new set of rules due to Bagramon's manipulation of the new world.
Trini and the others found out Ian was returning home, so they prepared a party for him, but Bagramon attacked. Also Seraphimon and Kokuwamon disappeared. Jason later finds out they're modifying Ian's old armor to make a new Ranger, alongside with saving Gumdramon.
The team felt confused and saddened by this fact, saying that Ian should be the new Ranger. But Jason tells them even if it isn't Ian, they need help. They arrive at the Digi-Center, to meet the Sky-Blue Ranger, who turns out to be none other then Ian.
Stingmon captures them, and later Ian, Sonia and Jason go to rescue them, but Jason gets injured, he takes off his helmet, but Charlie, Adam and Mary end up seeing who he is.
The three are brought to the Digi-Center and swear never to tell who the Digi-Ranger really are.
Some time later, she, alongside Dan and Bradley, were chosen to go to a Peace Conference in New York, meaning they had to leave. The team was sent to find the "Dragon Fang's Sword".
They manage to get the sword along with 3 new Digimon. Seraphimon tells Dan, Trini and Bradley not to worry, and that Charlie, Adam and Mary will replace them.
- Thuy Trang provided voice work for Trini, in a good case of irony due to the fact in the show Digi-Rangers originated from Thuy played the original Mighty Morphin' Power Rangers Trini, and an episode was dedicated to them after she died, the episode of Power Rangers Time Force Circuit Unsure and episode of Mighty Morphin' Digi-Rangers Navy-Blue Power.