It is not uncommon to have students show up at mat classes with some type of scoliosis, kyphosis or even a combination of the two. I would help her work as evenly as possible on both sides of her body. For example, when holding the arms up, to try to work with them at the same length during the roll up. Due to her kyphosis, she may also need a pillow under her head. One thing I would avoid is too much rolling up to her upper back. Otherwise, help her to find length in her spine and long reach through her arms as you work the through the basic mat exercises. And ALWAYS remind students in a mat class that if an exercise doesn't agree with you, then leave it out! Best of luck,