What is the most amount of weight i can loose by december? im 14 and 107 lbs...?

Simple answer... 1lb of fat is 2500cal. To lose 1lb of fat you must burn 2500cal... it's up to you how fast you can do that. From your description it sounds like you don't have much fat to burn though as you sound athletic and small to begin with. I'm sure you don't want to hear people tell you you're small enough so that's how much weight you can lose.