If you are female with a height of 159 cm then your weight should be 53.07 - 56.70 Kg and if you are male with 159 cm height then weight should be 56.25-60.33 Kg. These calculations are correct if you are over 18 years of age. If you are below 18 then you should inform about your age because age is necessary to calculate weight.
At 159cm (5'2), you should weigh between 104 - 131 pounds(47.1 - 59.4kg).
You are right at the upper limit of the normal weight for someone of your height, so really, you don't need to lose weight if you don't want to.
If however you want to lose weight to get a bit leaner for aesthetic purposes, that is totally up to you, you would simply have to focus on eating less and exercising more.
Focus on eating mostly vegies+lean meats with some fruits and minimize high calorie processed foods which will not provide the needed satiety for a low calorie diet.
You can find more info on setting this up here.