14 years old is still in the period of pubertal development, generally speaking, the penis can still continue to develop, clinically seen can also continue to develop 3~5cm. the measurement of the length of the penis is generally refers to the length from the pubic bone joint anterior to the head of the penis. The normal length of the penis of adult men in China is about 4~12cm, and the average length is about 7cm. The length after erection is about 8~18cm, the average is about 12cm. 12cm at the age of 14 has actually reached the average level. It is recommended that you can usually strengthen nutrition, eat more high protein food, appropriate physical exercise, maintain a regular routine to enhance physical fitness. In addition, try not to masturbate.