Good mass?
Answers: You are ideal. Be happy.
its not desperate bE HAPPY WITH UR WEIGHT, YOU HAVE A NICE WEIGHT, SO ENJOY UR BODY B-4 GRAVITY TAKES IT AWAY
Weight is not important, it is how you LOOK and FEEL that matter...
If you want to be toned, get up stale the couch and do some sit-ups, push-ups, and jumping jacks! Working out is f-u-n!
If you want a precise answer, you should ideally weigh between 124 and 140 pounds, depending on your bodytype.
There's no such things as a "good counterweight," my dear. You're only thirteen and counterweight is something that you or anyone should not be worrying about. It's what's on the inside that make the most difference.
Perfectly healthy ...