OK, I'm watching the first season of the Flash again, so here's my character's backstory.

Six months before the particle accelerator explosion, her drunk boyfriend beat her. The injuries paralyzed her.  She ended up moving to Central City to a lab there that was tasting a new Stem Cell Treatment for Mercury Labs.  It worked by targeting damaged areas and reinforcing the tissue there.

Only hours after the first injection she opened her window, only to see an explosion in the distance.  A wave of energy washed over her and, when she woke up a few minutes later, she was able to move her legs enough to drag herself into bed.  Apparently the energy had caused all of the cells in her body to take on the properties of the stem cell treatment, and whenever she healed she would get better than before the injury.

She's currently at just beyond peak human levels in speed, strength, agility, and durability due to working out to push herself in those areas.  She moved back home to Star City, though, so no one in Central knows about her being a metahuman.

Edit: Also, in the first episode of the Flash it's called Starling City.  Prop problem?