I suggest you know your basal metabolism first. Then make sure that what you eat remains at the basal metabolic level. You can download a mint APP, which can record the calories burned by diet and exercise every day.

It takes 7700 calories to consume 1kg of fat, and three months 15kg is equivalent to 5kg per month, and it takes 38500 calories per month. On average, it is about 1280 per day. This amount is also a bit large, and it is estimated that it is difficult to implement. There is no guarantee that you can exercise every day. It is suggested to set a small goal first and finish it step by step. When you see that your goal has been achieved, you will be more motivated to continue. Hope to adopt.