Health

Hi, my name is Megan and I'm 13. I have a question and I want to see if I can get help answering it. Last month I started on the 11th and the month before I started on the 15th and I haven't started yet this month and I'm not sexually active and Ive had my period for a year in February so if anyone can help me answer this question that I'm struggling with please tell me in the comments I can us all the help I can get.!