I need other women's opinions please!!

The last time I was on my period was 7-10 Feb, and I still haven't been on since-should I be worried? I'm 15 years old, I started my period when I was 11 and I'm a virgin. I even got a pregnancy test just to put my mind at ease and it was obviously negative. I'm going on holiday in April and I'm going to the doctors soon to get whatever medication you need to stop you being on your period for a month but I dont have a clue why I'm so late- I've always been regular. I need someone's opinion who has maybe been through this please! Thankyou x