Hi, Nothing to worry, this is common habit at this age due to more dominant of Testostrone hormone in the body. There is no harm doing masturbation to satisfy your sex excitement. To reduce masturbation, 1, remain busy with your study and daily work. 2, avoid thoughts of sex, 3,pass some time with sports and your friends. 4, see some good entertainment TV sereals daily. 5, go for regular physical exercises daily like running, jogging, swimming etc. Ok and take care.