Like some of her masked kin, calling Adventure Girl's superheroic training and acrobatic skill 'powers' might be the slightest bit of a stretch.  In truth, they're more accurately physical abilities that she has honed through intense training under Miss Adventure's tutelage, rather than inborn powers or superhuman abilities.  Jen has become a more than adequate hand-to-hand combatant, and has a natural athleticism that has been sharpened until she is now capable of performing feats of acrobatic ability. Her natural athleticism tends to give her fairly good range and accuracy with thrown objects, as well.

In addition to her martial arts and hand-to-hand training, Adventure Girl-- like her mentor-- regularly carries a small arsenal of supplies in her belt pouches, including the formidable namesake  Adventurrangs, a CO2-operated grapnel gun, smoke pellets, fingerprinting kit, and other crimefighting essentials that Miss Adventure supplies her with.  Often times, she will prepare herself well for whatever villain she and Miss Adventure might be facing.
 

Jennifer Harlowe was born to fairly well-off parents and lived a singularly normal childhood for the first thirteen years of her life.  She was always an apt student, and a friendly, extroverted sort of girl.  That changed when she and her parents went out to dinner to celebrate her father's raise at his job.   Unbeknownst to them, the restaurant they chose to eat at was a front for the activities of a small- time mobster that had made some big-time enemies.   Before the first course was even served, a bomb that had been placed in the main room exploded and started a tremendous fire that took out the restaurant and the neighboring stores.  Jennifer was thrown toward the front wall of the restaurant and likely would have died, except for the arrival of Miss Adventure, who braved the flames and pulled the thirteen-year-old outside to safety, just in time to witness the building collapsing, killing the remaining patrons inside, which included Jennifer's parents.  

Jen was utterly devastated and inconsolable, as was Miss Adventure.  The orphaned girl was saved from becoming a foster-child and spending the rest of her formative years in an orphanage only by the intervention of business mogul Candace Ellington, who took the young woman in as her own ward after being moved by her plight.  At the time, Jen didn't know that Candace was really Miss Adventure, and truthfully didn't care all that much.  After the shock and trauma slowly began to subside, Candace revealed the truth to her young ward, and shortly afterward, Jen asked if she could join Miss Adventure to help make sure that what happened to her never happened to anybody else. 

Miss Adventure agreed, and Jen's physical training began shortly after that.  The training slowly pulled her out of the quiet, introverted shell that she built around herself after her parents' death, and when she felt ready, she donned an electric blue and yellow uniform and mask and took the name Adventure Girl in deference to her mentor and friend, and after giving a good account of herself while operating with Miss Adventure, she became a member of the Justice Friends and later, fast friends with Janice Riley, AKA Bubbly Blonde, who is likely now her best friend in the world. 

Jennifer has been Candace Ellington's ward for nearly four years now, and has been Adventure Girl for about two and a half.  And as for her mindset, things are finally getting back to normal.  Almost.