Hi Mia. Irregular cycles can be caused by many different things, most of which are easily treated. Being overweight doesn t help, and if you can eat healthier and find a regular activity you like, it would be better for your overall health and cycle regularity. Though there are many normal weight young women with menstrual irregularities. The most common cause (1 in 20) of irregular cycles is a chronic condition cause polycystic ovarian syndrome (PCOS). In simple terms the natural rhythm of the menstrual cycle is blunted. One is resistant to the signals that cause normal fluctuations. The local doctor or clinic can check labs to confirm the diagnosis, and at the same time check a few other common causes like thyroid function and a brain hormone, prolactin. If PCOS is present, the easiest treatment is oral contraceptive pills. When you wish to become pregnant, which I assume is a long ways away, there are some well tried medications to help induce a regular cycle. Don t be afraid to talk to a gynecologist, but find one you like as you ll need to visit once or twice a year. I m glad you want to take good care of yourself. Smart girl!