Different people, different bodies, different results... however, the bottom line is, you generally have an easier transition if you're in your teens, early 20s, or even younger that both (which is very rare, by the way). Unfortunately, I only figured out I was trans just after my 18th birthday... so my voice was already long gone in the male range. It depresses me to think about how things would be different had I only realized things sooner... but, even then, there is no saying what my family would have thought and done about it or even if I would have gotten on hormones at that age. Oh well... it is what it is, I guess.