You will probably fill out as you get a little older. When I was your age and height, I weighed about 70 pounds.
I agree with April, If you are healthy, and you feel good, and you have enough energy, I wouldn't worry about it. A lot of young teen girls are skinny. From the height and weight charts I've looked at, you're only about 5 pounds underweight.
Well....it's still hard to see you in such a tiny picture! But if you're feeling good then I'm sure you're fine!
to see a picture just look at my profile I'm the one in the pink
It's hard to say without seeing you. You are pretty petite but you may just be small boned. This could very well be a good weight for you. As long as you're eating three square meals a day and snacks, getting some exercise without overdoing it, and feeling good then you should be fine. As long as you have enough energy to get through the day and you're not drooping or too tired to do normal stuff that kids do, then I'd say you have nothing to worry about. Hope this helps!