She has been a famous composer and musician in more than one lifetime, but we do not wish to intrude on her story or her privacy with respect to this history. But the talent is certainly evident and is all on display because it has been cultivated and developed over many lifetimes, and that is true of all who are extraordinary, who are a prodigy in one way or another. They are simply coming in with a greater connection to and command of prior talent that has been awakened and is manifesting through them in their new incarnation. This takes many forms. It may be an artistic talent, a musical prodigy, or someone with a genius IQ who soaks up information and seems to know things without even being taught.
This is a prior competency being reawakened and emerging in the current incarnation. So she is certainly precocious and is well prepared to engage with a musical life and function at a very high level. This is her purpose in coming—it is to bear witness to the divine origin of the soul and all creativity and her inspiration from her stream of melodies coming from somewhere she does not fully understand, and her stable of imaginary composers she turns to, to assist her, are all demonstrations of an interplay with the divine consciousness.
This is where such things come from—it is the source of the great writings, the great musicians, the great music and the great art as well as leaps of logic contributing to scientific discovery, innovation, and great literature. She is at once an example of the reality of the divine realm and the reality of what is possible among the new generation of humans, in particular, coming in with greater capability than before. While there have always been prodigies down through the ages, the sheer number of extremely talented people being born is a testament to the Shift in Consciousness making inroads and she is a shining example of this.