Possible at 13 yes, advisable no!
We home educate our son and part of that has involved learning about puberty and it's effect, stuff I could have done with knowing about 30 years ago.
As a male going through puberty you will hit a period where the hormonal switch will increase muscle mass and burn massive amounts of energy resulting in fat loss. This will happen regardless of activity leve, though of course if you are shaped like a whale it would be barely noticable.
If you don't have the energy available for any reason you will delay your development, and if that never appears can potentially stunt it permanently. The latter is in fairness generally only going to happen with long term severe eating disorders etc. so think more of the former.
You could be an early developer and have done this already, but if you haven't and try dropping too much fat now you could delay what is already a slow enough process, the chemical and physiological transition to adulthood.
The last thing you will want to hear at your age is be patient but that it the best advice, wait a few years until you are sure this has passed then work on the six pack.