Is it healthy for a 14 year old to weigh 146.5 pounds?

ok im a 14 year old girl and im 5'6. since school has started i have gained some weight because i used to be in athletics and wrk out every day but now i dont have enough time and i ran out of electives. I just stared doin some streching and chrunches every night to try and loose some of the weight. The fat i hav is in my stomach and its realy hard to get rid of. I lost weight last year when i did track doin all of the running. HELP ME PLEASE :D