Your "friend", whom we all know is simply YOU trying to to avoid making yourself sound stupid (which by doing so, have made yourself sound even MORE stupid), would be a complete idiot to touch anabolics at such a young age. You were given an answer by Mel22 (albeit a bit of a joke answer.....for what could only be a joke of a question), which you arrogantly disregarded simply because it didn't explain enough for you. Here's an idea - do your own research. Or better yet - get your "friend" to do it for himself.
The best cycle for your "friend" (oh for fucks sake....YOU) would be to continue hard training and proper dieting, taking full advantage of your body's already naturally high testosterone levels.
Do not even consider touching AAS until you're at least 24-25. Any earlier than that and you risk major developmental problems due to suppression of your HPTA, and as others said potential growth-stunting.
The only reason that isn't medical to touch AAS at your age (and NOT a justifiable one) would be if you absolutely 1000000000% intend on devoting every moment of your life from here on to bodybuilding, and have no other goals than to become Mr Olympia. Knowing this isn't your intentions, I must repeat once more - DO NOT TOUCH AAS AT YOUR AGE.
I'd recommend speaking to a therapist of some kind though. Multiple personalities could also pose issues for you.