Would a car need new brakes if it was hit and it skid a good 6 feet?

About 5,000 miles ago, my car was parked and hit pretty bad from the back. It skid about 6 feet or more. I have 17,700 miles on it my car started to make noise. I took it in and they said it was the brakes. I was told by several people that cars usually do not need new brakes until 30,000 miles. So could the skidding actually of done some kind of damage to it.