I'm 19 yo going on 100ml/week testosterone cypionate for delayed puberty. typically how long could i expect to reach adult genital size?

3 - 6 months: Worth being checked out on a monthly basis.

Depends: On what you mean by normal? Bear in mind, we are all different. Also, keep in mind that some hormone therapies may lead to testicular atrophy. Discuss this further with your doctor, if may seem like an embarrasing question to ask in person, but trust me, they'd heard it before.