Bro, first off, nobody is going to just throw a source at you. Talk with people around here. The mod's are really good people. Infact most of the people on this board are all good bro's. They will help you out the best they can. I look at your pic, and I think of myself when I first started. I worked out hard for 3 years, before I ever thought about the juice. I wasn't even so sure then if I wanted it. When I mean hard, I mean hard. If my friends were going to the movies, and I hadn't worked out for the day, I would tell them that I would meet up with them later. Then I would go get my workout in. If I was going to a place that I wasn't sure if they had good food source (the beach, friends house, etc), I would bring a cooler with me. In it I had water, yogurt, tuna and something like a banana.
I'm not going to tell you to wait until you are 20-23. If I do, you will probably just do it anyway. I will however tell you to seriously think about it. Once you start, you will go back again. You are fooling yourself if you think one is all you will do. Don't worry so much about fat levels, and 'six packs'. You look lean, to gain a lot of muscle, you have to gain a little fat. Don't be scared of it. Concentrait on building a solid base with lot's of muscle. Then once you do that, you can worry about being 'cut' and defined.
Use lot's of compound movements. Don't get into anything too elaborate. For your chest do bench press, incline press and dips. For your back try chins, deadlifts and barbell rows. If you want to throw in extra work for your arms do some barbell curls, close grip press and lay off the cables. Try barbell clean and press, and lat raises for shoulders. Squats, straight leg deads and standing calf raises are awesome for legs. Don't worry about running around the gym doing this machine or that, or doing bullshit like nothing but flyes for chest. Do the big lifts. Compound movements. Combine that with ton's of food (try the eat everything in site diet. Make cows 5 countys over scared of you), and you will watch the muscle come.
When you think you are ready to dedicate yourself that much. When you know you love bodybuilding, not for the looks and girls, but for the wonderful feeling it gives you. For the self esteem, energy, confidence, etc. Once you feel you can stop worrying about putting on a lil fat, and concentrait more on eating lots of good food. Then and only then would I advise you to look into steroids. Even then, give it some serious thought. Bodybuilding should be a life long commitment. One that will help you enjoy life more, and add to it. It shouldn't be just a flase in the pan thing to do, for vanity reasons. Good luck, and I hope you decide what you want to do....