U mean premature ejaculation.
U do stamp yourself with it.
Most common reasons are stress ,sedentary lifestyles, medications or alcohol.
Learn kegel exercises and stop _START technique .
Next Steps
Do not involve into such medicines as you are very young.
Relax yourself.
Do regular exercise or walk for atleast half hour daily.
Health Tips
Visit site for more details on premature ejaculation.
http://mydoctortells.com.