First off, everyone is different. I know people my height that weigh 20-30 lbs less, and are healthy, but if I am even 5lb less than I am (still a healthy weight, and done by lifting and eating healthy), I look gaunt. Its not pretty. So everyone is different.
Secondly, these threads are harmful and destructive to anyone with or borderline eating disorder. I cringe every time I see them. It becomes a "I weigh this much...oh, I weigh this much..." and a contest on who weighs less. It scares me. I've seen the damage an ed can cause and I'd hate to see anything on these wonderful boards that encourages it.
Thirdly...weight doesn't matter. Do you feel good? Is what you eat healthy and balanced? Does it include appropriate amounts of protein, carbohydrates, fruits, veggies, calcium, and good fats? Do you get regular exercise (this is likely, as you are in gymnastics)? These are the important things, not your weight.