If you are trusting this teacher with the musical education of your children, why don't you trust her to answer your questions?

And if you can already speak English, repeat stories you already know, and make up new ones, why bother to learn to read and write?

Unfortunately, students leave piano after a couple of years because they do not understand that it takes many years to become a proficient musician, as well as be able to sightread easily. Most of the time it is because they lose interest in practicing, because practicing is not FUN. And it is only through practice that you can become good at the technical/coordination aspects of playing the piano.

I think you have some concerns that need answers, and the first place you should be able to go is to your child's teacher.

And if you are happy with your childrens' progress so far, why do you feel that it needs to follow a different path? IMO 1 1/2 years is not enough time to decide "what path to take", because you have not even scracthed the surface. Relax, and let your children enjoy making music without the stress of having to meet your expectations.

What instrument do you play?