No it is not.
There is no such thing as 'normal' it depends on your parents height. There is an average, and 'normal weight for height'.
Height 5'5" and weight 50 kg
The normal weight is 130lbs
A normal, healthy weight for a 13 year old averaged sized person should be in range from 105 pounds to 120 pounds.
The normal weight would be 110 pounds
yeah, that's a normal weight.
The Normal weight for a 5"3" or 5"4" 13 year old boy is 107-110 pounds.
7 or 8 stone
There is no good weight for a 13 year old. But the normal weight is 130-150 pounds
Normal weight = 18.5-24.9