Yeah you don't wanna play with your hormones when you're super young. I'll probably get banned if I talk a lot about them but I've cycled before if you know what I mean. I had naturally high testosterone so it was easy to put on muscle so I made the decision to push it further - And after cycling 3 times I stopped... I'd made insane progress both naturally and unnaturally.
It's like Lee priest says, if you're at the point where you physically can't put on muscle if you're that big - Then use steroids... Up your calories and train hard, pal...
And as a young guy, you won't have good channels to buy through - You might be taken advantage of buying direct at gyms - No online **** either.