I'm 13 to, I don't think you should be worrying about your weight because as long as you are healthy it's good to be a little overweight as we are still growing so it will accompany our body right when we are older. Also height is important because height changes what weight you should be but if you are really worried then ask your mum to weigh you on some scales or to take you to the doctors and they can weigh you instead for a precise measurement. But don't let it get in the way of having fun!!!!!
The ideal body weight is based on the person's height and body built. All these take into consideration when finding ones ideal weight.
Hmm it is depends on your height. I suggest you to try BMI measurement to know which body type you have