Im 5'3 at roughly 125 lbs (short & skinny)...even at 5' at that weight, its not overweight or anything to worry about. Plus, you are 16! Your body is still going to change quite a bit. When i was 16 I weighed 140lbs and by the time I was 19-20yrs old I was the weight I am now (age 27, same height as 16) and id never worked out or anything in those years. I kept my "baby fat" for a long time. I once read somewhere that many people are still growing/changing until atleast 21 years old...Long time ago, but i think thats the age I read. Anyway, its good you are being active though, keep it up!