Muscle is more dense than fat and takes up less room, so you can technically weigh more and be a smaller size. But it takes a lot of weeks/months of hard work for a women to even gain one pound of muscle. When you first start weight lifting, your muscles retain water to help them heal. This can show on the scale as a temporary gain, no loss, or small loss. As you build muscle, your metabolism will increase at rest, which in turn will help you lose better and maintain the weight easier at goal. But it takes time. Take your measurements so you can see loss of inches. You should start to notice fat loss in your body soon. Keep at it and the scale will eventually follow. Good luck!