Bella Dawn Parker’s grandparents worked at the Nevada Atomic Weaponry Test Site for Robert Oppenheimer; this is how they met. Their son, Robert Jonathan Parker, also met his wife (Emily Katonic) at work, this time at the Groom Lake Research Facility (Area 51). Nobody was shocked when Robert and Emily gave birth to a bouncing blue baby girl…there was a high percentage of mutant kids coming from the workers at Groom Lake, and Las Vegas is not a bad place to raise a mutie kid—nothing surprises anyone there.
Her ability to heal first showed up when she was quite young, first when she hurt herself playing, then she quickly realized she could also heal her playmates without them having to go to their moms (and maybe confess they had been doing things they shouldn’t have). This made her rather more popular than less, and by the time she was in high school, she was a regular assistant paramedic at sporting events. That (and the fact that she just had too many interests to want to settle into an 8-year academic grind) was what decided her to become a paramedic rather than go to college, although she is certainly intelligent enough to have gotten an MD.
So with dual-course taking, highschool and paramedic training, she became a full-fledged and working paramedic before she was out of high school. With her healing abilities she was also recruited into the Las Vegas branch of Echo Rescue as a Mach One.