We can see that taking gear at a young age with f-up your normal growth. . .but for taking gear at an early age. . .i did my first when i was almost 20, about 90 to 95% of all hormone production in the body is normalized (at the levels they will be until they drop in the mid to late 40s) at around 19 years. Most guys don't technically stop gorwing (when final growth plate development is finished) at 22, but depending on your build and how long u have been training will greatly effect plate development. I have been training for 6 years and i am short and i will be short (5'9") for the rest of my life. Taking gear in moderation. . .no more than 500 mg week of any test shouldn't f-u up too bad in the long run. My first cycle was sust250 twice a week and 25 mg dbol a day for 6 weeks and I saw modest gains about 10 lbs and kept all of it. So i think if u do it right and and make sure to limit urself that taking gear before ur 21. . .not too much before would be fine.
PS my dad is an MD.
I am just in this for the opinions. . .lemme know what u think