While remaining healthy, you can lose up to 2 pounds per week which would mean, in theory, losing 12kg in 3 months which would be near your target. However, in reality, weight loss will plateau and your target seems particularly difficult/unhealthy: losing more than 2 pounds a week can lead to health complications. However, you can look better without just losing weight - doing some gym lifting would help you both build muscle and lose some weight from burnt calories too.