Lumbar vertebral body compression fractures are well-recognised following an axial load with or without flexion. Not surprisingly, there is a wide spread of severity, ranging from a simple "buckle" of the anterior part of the body of the vertebra to complete disruption of all the bony elements, ie. including the posterior parts (pedicles and laminae). The latter is serious as spinal stability is compromised. From your description, I expect the injury was at the more mild end of the spectrum - your doctor should be able to confirm this.
Fractures will generally heal in 6 - 8 weeks but will continue to consolidate, or strengthen, for months. Your daughter should therefore allow time for sound healing to occur before she "tests" her back again. I suggest a minimum of 8 - 10 weeks. She should also consider physiotherapy to maintain good torso musculature / posture / flexibility. Analgesics and anti-inflammatory agents are sometimes helpful. A full recovery should occur - if the vertebral structure is not significantly altered.
(my day job is trauma & orthopaedic surgery)
Regards
AP