when u start
When you first start your periods they are likely to be irregular. It’s common and normal for you to have one and then not have another for a couple of months, or for them to arrive after three, four, five or six weeks. They will probably be all over the place for the first two years.
Of course, periods will stop if you have sex and fall pregnant or if you are dieting too much. But if you’re eating healthily and haven’t risked pregnancy, then it’s simply the natural pattern. You don’t have to do anything to start them again – they will, in good time.
There’s a good book on the subject – Have You Started yet? By Ruth Thompson. Get a copy and have a chat with someone you trust. Is your Mum around to help you? She or another female relative or friend could reassure you.