I just turned 14 and I have an erect penis of about 5.75 inches. I know that my final size is still undetermined. I am 5'8" and have not had my growth spurt (I'm projected to be about 6'3".) I am also somewhat overweight (155 lbs, but still very strong.) How much can I expect to grow by the time I'm 18-21, assuming I lose some weight, don't smoke, and get to 6'3"?