How much weight should i lose if i'm 131 lbs?

There are different body types so that totally depends on that. If you feel like you should lose weight or want to be leaner, then look into how to decrease your body fat percentage. I suggest not eating wheat - bread, pasta, cereal etc. That's always a good place to start and never go back.

According to WHO, body mass index (BMI) is a term that is used for accurately classifying overweight and obesity. It is defined as the ratio of a person’s weight in kg to the square of his height in meter (kg/m2).

If you want to know How To Check Whether You Are Overweight, this informative write up can help you.