18 years ago - Cassie Sandsmark is born the daughter of noted anthropologist Helena Sandsmark.
12 years ago - 6-year-old Cassie first meets Diana Prince when she starts working with Dr Helena Sandsmark to study Amazonian influence on the outside world
11 years ago - 7-year-old Cassie gains an adopted big sister when Donna Troy stays with her and her mother Helena Sandsmark.
4 years ago - 14-year-old Cassie travels with her mother Helen Sandsmark to Themyscera while she works on her book, and steals several Amazonian artifacts to become Wonder Girl. When she returns them, she manages to gain an audience with Zeus & impresses him, gaining her powers. Diana Prince and Artemis agree to help train her on Themyscera. She soon joins Young Justice.
3 years ago - 15-year-old Cassie is recruited by Cyborg into the New Teen Titans, and is given her lasso by Ares. She battles Edgar Cizko and saves Diana Prince from him.
1 year ago - 17-year-old Cassie goes to the homeworld of the Titans of Myth with all the surviving Titans to save Donna Troy. She and Connor Kent begin their relationship.
now - 18-year-old Cassie steps up to lead the Titans when Tim Drake leaves to find Batman, rejecting Ares influence. She asks Argent to join the team again. She bonds with 13-year-old Krypto after Connor Kent's death.
Cassie has had an absolutely fantastic run in her time in DC comics, growing in leaps and bounds both as a hero and as a young woman. Unfortunately, her exceptionally well-written relationship with Connor Kent ended with his death, and suddenly it seemed impossible for anyone to write her without dwelling on her grief. Every effort to make her grow past in seemed to make her angrier and more emotionally distant.
It's probably a real testament to how complete a character she had become that we can easily perceive the change in her personality as she undergoes such a tragic loss, but that's always been what's so fantastic about this character, that her personal growth has been an integral part in her story.
We clung very closely to her story as depicted through her pre-52 career, even including her time taking over as leader of the Teen Titans after the death of Connor. We'd like to alter the way she handles her grief a bit, allow her to grow through it without succumbing so much to her anger, but otherwise, almost everything that makes her great shines through in her every appearance.