Everyone is well aware that boys go through a voice change in their early adolesence. For the most part boys and girls have similar voices (quality and range), and boys voices will lower a full octave when they become a man.
However, girls go through a voice change as well, just the changes are different, and how a boy's or girl's voice will change can never be predicted exactly even by the most seasoned professionals.
Further, the human voice continues to change for many years and even throughout life until death, so a person's voice can possibly be many different types over the years. The teacher will help the student develop the vocal instrument in all ways possible - allowing for full flexibility to change if the voice should change and respecting any current limits even as those limits are being gently stretched.
A song that sounds good today may not suit the same person's voice a few years later, and vice versa. No singer should aspire to a specific voice type as this may not fit how the voice develops! It is best to embrace whatever fits the instrument you have and have right now!