no, you're not overweight...however, i was even bigger than you at 12 ( i weighed 145 ) and my friend convinced me to join a swimteam. DO THE SAME!! swimming does incredible things for your body!! it's good because it doesn't put any pressure on your joints, and it makes your heart stonger, builds muscles which will lead to more fat burning...it may seem hard at first but DON'T GIVE UP NO MATTER WHAT YOU DO!!!! i wanted to, but i didn't, and i've apparently really changed (i look like i'm 115, but i weigh 130 because of muscle)...good luck!!!