Congratulations, you are at a normal and healthy weight for your age!
We come in all different shapes and sizes, so it's no good trying to compare your weight with your friends and family. It is important to recognize that your ideal weight will depend on the following factors:
Age
Height
Gender
Body Mass Index (BMI)
The basic calculation used to determine a person's BMI is by dividing your weight in kilograms by your height squared. So in your instance, this would be:
Alternatively, to spare yourself the maths, you could pop down to your local chemist and ask the computerized scales to do it for you.