Thank you for your question.
There are many causes for early ejaculation or as you call it premature ejaculation.
You do not mention if you are facing the problem when you masturbate or when you are with a partner and whether it happens every time or only some of the time.
Generally, being able to control ejaculation is a learnt habit. If you practised masturbation in your teens and rushed it because you were afraid of being disturbed you have learnt to ejaculate quickly. You can learn to delay ejaculation by managing your arousal and practising pelvic floor exercises. Very rarely if the cause is severe anxiety you can benefit from medication.
Please read 'managing premature ejaculation' by Metz and McCarthy. you can find it on Amazon
if you are still not able to overcome the problem consult a sex therapist who can guide you better.