Eva, Aleja's mother, was a prominent lawyer in Chicago when Carlos, Aleja's father, met her at a charity gala for the hospital he worked at. His resumé impressed her: completed his medical degree at Johns Hopkins at the top of his class, then his residency at a premier New York hospital, and he was now a promising oncologist in Chicago. In three years they were married and a few short months later, Aleja was born.
Aleja's first magical experience was when she was six. Her father, who worked night shifts while she was little so he could spend time with her, had just come home and in to check on her when he noticed the tigers on her wallpaper were...moving? Initially he dismissed it as hallucinations, but when it happened several times--and especially when the notification came from Ilvermorny--he knew he hadn't been hallucinating.
At Ilvermorny, Aleja was sorted into Pukwudgie. She was an excellent student--not quite the top but definitely up there. Even though practical lessons were her her favorite part of school, she most enjoyed her Magical Theory class. From her second year on she played quidditch (she loved playing beater but played chaser okay as well. keeper and seeker both were too idle for her to really enjoy.), despite a rather nasty fall from her broom (she swung her bat a bit too hard and just slid right off) in her first game. Her mother, whose father was a star rodeo cowboy in his youth and later owned a horse ranch in Mexico, told her that you can't let a single fall keep you off forever. ("You have to get back on the horse," she said. "These things happen, so all we can do is try again and remember not to make the same mistake.")
During the summers they would go as a family to visit Carlos's parents in Cuba and Eva's in Mexico. (One parent would take two weeks starting one week before the other parent so they got two whole weeks together but Aleja got to spend more time with her grandparents.)
She went through medical school intent on becoming an ER or Trauma surgeon, but she dropped out of her residency after less than a year, despite being one of the most promising. She lost a patient she knew she could have saved with magic and knew that if she continued on hler current path she would break down and use magic.
Her grandmother on her mother's side died shortly after, leaving Aleja the ranch in Mexico. Although Aleja loved the ranch and the horses, she didn't want to spend the rest of her life running it, so she promoted the ranch hands' foreman, a man in his late forties who had worked on the ranch for three decades and was also a close family friend, and made sure he was managing well with his new duties before pondering her remaining career choices. For most of her college years she played with a minor quidditch team (it took some creative class scheduling on her part, but she managed to pass off the few class days she missed as sick days), and she figured she could try to get back into professional quidditch if she shaped up again. As she was now spending most of the year in Mexico at the ranch, she had enough space that was far enough from prying eyes to practice in the air.
Eva had been feeling intermittent chest pains in the time leading up to and during Aleja's medical school graduation ceremony, but she thought she would be fine at least until she congratulated her daughter. The heart attack hit during their little celebratory dinner (she told herself that if she started feeling off again she would call 9-1-1 immediately, but she didn't caych it until it was too late). The doctors did their best but couldn'tget her stable. Carlos confessed that she's mentioned chest pains a few times but blew them off as muscle strain from lugging around her case files. Had she come in sooner, she would have lived.
Carlos died of late-stage brain cancer--it was too deep in the brain to operate on--one year after Aleja dropped out of her residency. He didn't tell his daughter until he was hospitalized at the very end.
After her father's death, Aleja went back into Medicine, becoming a trauma surgeon like she'd dreamed. Balancing work and quidditch was difficult and took lots of wideye potion, but she did it, and when she made the Mexican national team she put down the scalpel due to the training commitment.
After the Quidditch World Cup, she went back into medicine, this time at St. Mungo's.