a 4 pack at thirteen? sheesh, where are the parents...not to mention you haven't even gotten the fundamentals of math down. The more you drink, the less there will be! You can't drink a 4 pack and all the sudden 6 more find their way to you, if that were the case, I think the unemployment rate would be higher!
Actually, the muscle groups that produce a six pack are there, in your body right now. You dont suddenly group another muscle group at a certain age. As you grow up you will notice them more, especially if you keep yourself physically fit.