Ok , listen I mean to be polite but I have to tell you do not know anything about steroids and the use of as safe as possible from your post. And I have never read a forum that said anything but age 25 being the time minimum safe age.
Please read ALL the sticky posts. They are labeled sticky and found where you came in to start your thread. Man there is so much to know before you stick your ass with Testosterone. This will change your hormonal balance and other you will encounter many side effects.
I for one will not tell you anything as to going about this until you get more educated in what you want to do here. Many and I will say most of the guys and vets on here will say the same. We want to and will point you in the best direction to find info and help explain what you read.
Good Luck