Answer:
Fat comes off the body as a whole, not in specific areas, no matter how much you target them.
Working out is a great way to lose weight, however diet will be the single biggest factor in your weight loss.
Working out is not likely to increase your leg size, unless you spend a lot of time squatting heavy loads, and even still (assuming you're female) it's very difficult for women to gain muscle mass, especially compared to men.
As fat comes off as a whole on your body, if you're female, your legs may be the last area you will see change, as this is a common area for women's fat stores. However, losing weight will cause everywhere on your body to look leaner and more nice.