Final answer:
Given that 17-year-old Jana has reached skeletal maturity, it is unlikely for her to grow taller before she turns 18.
Step-by-step explanation:
Jana is 17 years old and has reached skeletal maturity as indicated by her X-ray results. This means that her growth plates have likely closed, making further height increases very unlikely. During puberty, most girls experience a growth spurt that begins between the ages of 9 and 11 and can last for two years or more, during which they may grow up to 3 inches per year. However, by the time they reach skeletal maturity, which typically occurs by age 15, it is unusual for them to experience significant increases in height afterwards. Considering Jana's age and the doctor's assessment of her X-ray, it is improbable that she will grow the additional 4 cm she hopes for before turning 18.