I want to buy a new babolat tennis racquet i am going to be15 and am using contest si.?

I would suggest the Babolat Pure Drive GT. Don't get the Plus version though, it is longer and heavier and for a person who is only 5 ft. tall it would be too much to handle. The Standard version its a great racket, it will help you a lot with serve and ground strokes. It has the best combination of power,spin,and control on any racket i know.