Here's what Istra's sounding like after about 6 of her voice lessons. Her seeming natural aptitude is being combined with the new vocal control techniques she is learning. From a young age she has (for reasons unknown to us) attempted to mimic an operatic vibralto, and loved singing soaring songs. Now she is learning how to hit higher notes without getting louder, proper breathing, and other such details.
This recording is just casually done on a tablet. She's not trying very hard, and can do better. Still, this gives a sense of what she's up to.