Well, Starfire's origin starts on Tamaran. On her home planet, she faced a lot of political intrigue. As a princess, she was supposed to inherit certain powers and a throne. But her sister Blackfire's envy led to her being betrayed. She was then enslaved by some cruel beings. However, Starfire has a strong will. She fought her way out and her journey brought her to Earth. Here, she found a new family in the form of the Teen Titans, and she uses her powers like flight, super strength and energy projection to protect the Earth and her new friends.
Starfire's age varies depending on different storylines and comic arcs. But generally, she's often depicted as being in her late teens or early twenties.
No, they're not exactly the same. DC Comics is the original source of the characters and stories, while the DC Universe is a broader platform that includes various media adaptations and related content.