Welcome to healthcare magic! Masturbation is common at your age. Generally due to lack of privacy , people want to masturbation quick and avoid risk of being caught. Thus it becomes a learned behavior and along with this performance anxiety aggravates the situation. Therefore premature ejaculation can be tackled with proper sex advice. Learn kegel s exercise ( google it), squeeze technique by master and johnson may be helpful. Exercise regularly, eat balanced diet and don t worry much about it.