Complications
Motivation—Learning: Gwen is a dedicated student of the arcane arts and wants to learn everything she can about her powers.
Motivation—Doing Good: Gwen is a nice girl despite her dabbling in the dark arts and wants to use her abilities to help the world the best she can.
Responsibility: Given her mom's history as a defender of the mundane and magical worlds, Gwen feels responsible to upholding that legacy.
Secret: No one can know that the bookish high school student Gwen Jones is in fact the magical spell-slinger Magical Girl!
Gwendolen "Gwen" Jones always knew she was special. Well, not special exactly. Magic isn't a thing she discovered. It was omnipresent in her life since she was a child. That's what happens your born into a family of witches and warlocks. The Jones Clan were a family of mages from the Old Country, who immigrated a long time ago to escape persecution from a land that hated and feared for usually unfair and bigoted reasons.
It's for that reason that Gwen grew up hiding her powers and natural skill with magic from those outside her family and the wider magical world. The thinking went that the rule of shade would protect them from a return of witch hunts and burnings... until other, stranger superhumans started showing up in the world. The advert of the age of superheroes brought great changes upon the world of magic, with several witches and warlocks seeing it as an opportunity to finally be accepted by the mundane world.
Gwen's mother was one of those mages, and she used her spellcraft to become the superhero Magick, a prominent name in the hero community. Unsurprisingly, Gwen looked up to her as a role model and at an early age aspired to follow her mother's thought steps as heroine even as she juggled her studies in magic with more "normal" social life in the mundane world.
That all changed when her mother disappeared in Doomsday. Distraught but determined to do what she could to fill the needed role left by her mom's wake, Gwen took up her mantle and entered the hero scene as Magical Girl... much to the chagrin of her worrying father.