Your cat could be bored. I wouldn't reward her with attention when she is biting you. Instead give her some "time-out" by placing her in a bathroom for about 10 minutes. However, when she is behaving nicely, I would recommend scheduling some play time with her. Try to stimulate her natural hunting instincts and burn off some of her excess energy. Cats are natural predators, unfortunately we try to force them to live a life that is convenient to us. This results in a cat with excellent hunting skills being forced to live indoors where there is nothing for them to do. You might also consider another cat as a playmate for this one. Please remember to never shake your finger in your cats face or hit her. This will only encourage her to attack you. If the problem persists, I would recommend contacting your veterinarian for more suggestions and possible behavior modification drugs.

It is impossible to say how serious the problem is with the information that I have been provided. I think you could answer that question better than anyone. If you cat is becoming more aggressive and beginning to injure you, medication may be the answer. Especially if trying to retrain her is not working. I cannot speak for every veterinarian, but I try to use medication as the last course of action in this type of situation.