Early in puberty. Testicle enlargement is first sign of puberty. Testes then produce pubertal levels of testosterone which in turn drives the other pubertal changes, the next being penile growth. Please don't worry.
14. The average age for puberty to begin for males is. 14. Just like every thing else in medicine there is a lot of variability, so children begin before that and some after but all are in the normal range.