A lot of girls have irregular periods, me being one of them. I once missed mine for a couple months! But anyways, it's nothing abnormal and it isn't something to stress about. If the distance between your period becomes worse, ask the doctor what you could do to control this. It may have something to do with your ovaries, which in my case it was. My doctor prescribed me birth control pills, and my period maintained regularity after that. However, this also depends on your age. But do not stress out, talk to your doctor if you have any concerns, I'm sure they will help you out. :]