What if your a 48 year old female i weigh 140 pounds 5 foot 2 inches how much should i weigh?

For a 48 year old female, your weight is perfect. My mother is 49 and she weighs about the same as you. If you feel uncomfortable with your weight, you should walk a lot, and swim a lot. Swimming burns many calories. Walking burns the fat in your legs, and also is good for the stomatch.