My daughter is going to be 14 next month. She has been using the same rackuets for the last 3 years. She hits hard ,has powerful serves.She is not so consistant, some shots can go wild. She takes classes and plays about 5 times a week.She is not so tall. I really want to buy her new rackuets,but she said no,she is not interested in to try another rackuet. Any ideas ?