Period keeps coming early. HELP

I am 15 and a virgin. I have had my period for 4 years now. I have always had a regular period. 2 months ago, my period was fine. The next cycle came 2 weeks early and I didn't have any of the symptoms I usually have when I am on my period such as gastro. I just let it go think it was a one off thing. But this month my period came one week early. Is this normal? Am I ok? Is my period going to be like those girls who get it twice a month?

a lot of things can effect your period like diet, stress, physical activity, plus your still growing. I would keep an eye on it and if you periods get to close to each other than go talk to a doctor but right now I wouldn't be to worried.