Hi. I am 25 year old. A virgin yet. I was having my regular periods every month. I had my last period on 3rd december and still didn't get my periods.

Some possibilities. In a woman with regular periods, some causes of a late period include: excessive weight loss or weight gain, increased exercising, emotional stress, having an illness, traveling, medicines (like birth control pills), hormonal imbalances, etc… seeing a doctor is a good idea if symptoms are persistent, recurring, or worrisome. Pregnancy is the common cause of a missed period, if sexually active.