Im losing weight?!

So over this summer I wanted to lose weight by exercising but I have been doing stuff all summer. Latley I have noticed that several pairs of shorts and kapris I bought right as summer began are getting larger on me. I'm 16, 5'3", and I weigh 186 lbs. i know I am a little chunky for my height but idk. But I an kinda confused as to why I am losing weight. I have lost about two inches off my waist. I do not have good metabolism but I have cut back on how much I eat. Could that be a factor???