I'm thirteen and a girl... I weigh 48.9 kg and am about 153 cm : am I over weight??

No.

It would help if you used pounds, feet and inches.

If you don't remember anything else, you must remember this. Don't you ever let the media tell you how you should look or how much you should weigh. I'm sure you are a beautiful person if you can just be yourself and not anyone else.

Nope, that's about the average weight to be at. And Zack is completely right, it's all about your health and mental health in general!

No, that's pretty average.  Don't worry about how much you weigh; it's just a number.  If you're really worried, you should talk to a doctor.  I know that here, you can request to speak to a doctor by yourself at any age if you don't want to speak with your parents in the room.

I don't think so. And at the age of a teen, you need a lot of energy to grow and develop every day. Therefore, instead of trying to lose weight, you should have a healthy lifestyle and diet. In case you are wondering what kinds of foods to stay healthy, this article may be helpful for you: authorityremedies.com/top-superfoods-for-women/