CMT is one of the Muscular Dystrophy diseases. And according to NIH and the CMT association websites normal onset of the disease is in early adulthood and the disease has a slow progression. It also says that near normal life span can be expected.
From birth onset and end stage of the disease at 5 years old would seem to be atypical for this disease.
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Sound like she has a rapid onset if she is having respiratory issues at age 5
In CMT type 1, progression of the disorder is usually slow even if it presents in early childhood. In some children or adolescents, there may be periods of rapid progression that last for months or years followed by prolonged periods without change (plateaus). In some cases, the progression occurs during growth spurts, but not always. The pattern of progression and plateaus is distinctly unpredictable. The possibility of superimposed acquired neuropathy may be considered if a change in clinical progression is noted, especially in adults.