'Never' is a long time. However, the smaller you are the less energy you need to start with. So to create a big enough calorie deficit to lose weight you either need to eat next to nothing (bad idea for obvious reasons) or you have to do significantly more exercise than normal. And the progress is slow either way.
If you have 'muffinage' you should look at the quality of your diet. Many slim people (and you are slim) who have a poor diet can end up looking flabby or puffy because of fluid retention. If your diet, for example, contained a lot of processed foods, salt, sugar, artificial sweetners, caffeine, alcohol, preserved foods, packet foods, ready-meals etc., then that would be the thing to change before you start on the carbohydrate or even the calorie content.
If what you want is a toned, leaner body the other thing to understand is that 'dieting' (especially when you're a healthy weight) tends to result in the reverse. Deprived of energy the body will use lean tissue as well as fat to make up the shortfall... so you can end up losing muscle. Rather than being toned and leaned you can experience the awful problem of 'skinny fat'... ie. thin and out of shape.
So I'd suggest you aim to get your total energy needs for a while, pay attention to the balance & quality of your diet, drink plenty of fluids and take regular exercise. You may not end up weighing less but you'd be a much better shape.