I would recommend you attend the ER to get her examined by a doctor. She may need scans to check if there is any brain injury
. However, if the doctor feels that the impact has not been severe enough to need scans you may be able to take her home with instructions on what to observe in case anything changes.
She may develop a headache from the bump. I would suggest you give her paracetamol
according the instructions for her age/weight.