Bro I no how u feel about wanting it now!!! When I was 18 I was playing football and wrestling and I wanted that "edge". I had a coach, it was obvious that he was juicing. Talked to me and another player and he said, "why take that next step when u have so much potentional right now". It really sunk in man. He knew me and this other guy were wanting to take steroids do to gossip. So I decided to wait. I ate like crazy, trained like crazy and made gains naturally. If your at a plateau, change it up and confuse your body, it's all about your mind and training and when your not training diet and rest. I would wait till I am at least 21 if not older. Enjoy being healthy and enjoy not having to go to the doctor for blood work and all that good stuff comes along with this game. Wish you the best of luck. When I was 18 I was 6"2 230-235 natural. Not the leanest but strong and got a scholarship to play ball. Do it natural lot less complications and money, just for a while bro.