As your age is just 23 yrs, first of rule out weather there is any underlying disease for weight gain, like
thyroid,
diabetes.
Basically our weight depends on the calories we consume and our expenditure of energy, if you consume more calories n burn less then the extra calories that u have consumed are stored in body as fat, so make sure that take only that much calories which is required for ur daily activities, for loosing existing fat reduce calories intake n increase energy expenditure, reduce carb intake, oily fatty food, increase fibers n protons in your diet, take lots of fruits n salads n drink plenty of water. Follow this n revert me back after 2 mths.