Hello
Many of such fractures are known to unite with even closed reduction and cast (what your doctor has done). Although some deformity maybe seen, it may take 6-7months for the deformity to disappear. Functionally should not be a problem and she will gain nearly normal movements. But if you don't want to wait for this period and want earlier mobilisation protocol, then you can choose for surgery.
Next Steps
kindly consult for detailed resolution of your symptoms