Is it normal for a 14-year-old girl to have her period once every two weeks?
It is common, but not normal. There are lots of reasons for that to happen. And a few different ways to stop it, but none that I know of can be done without seeing a doctor. You should talk to your parents or another trusted adult and go see a doctor. I think there is no real normal when it comes to your period. Every one is different. I never had a normal period. I would bleed for weeks sometimes and sometimes I would not bleed for months. I never had PMS when I was a teenager but after my first kid I knew it was coming well in advance. At your age your body is still changing a lot and maybe sometimes it just doesn't know what to do. When I was 17 I started taking the shot and it fixed all my problems. I've only had 6 periods in 8 years and that was when I quit my birth control to have my son.