Hey bro,
Welcome to the board!
What the others said is true. At your age, your natural testosterone is very high. DO NOT use roids yet. You need to hit your natural plateau first! This is very important. The other thing is you need to have been working out for a few years naturally before even considering roids. What happens is if you took roids now, your strength would skyrocket, but your ligaments and tendons won't be able to keep up with the stronger muscles and you WILL hurt yourself! This is not an opinion.
If you want bigger muscles fast here's what you do. I promise this will work, I did it myself years ago:
At your weight, you are definitely not eating enough. You need to eat as much as possible! I meant that! Shoot for 4-5 thousand calories a day. This is tough to do...you'll be eating every 3 or so hours. Get a LOT of protein in your meals. You should shoot for 2 grams of protein per pound of body weight. Use supplements to help acheive this....mass builders, MRPs etc.
The other key is to start lifting weights! Go for as heavy as you can for 6-8 reps. Stick with the basic power lifts such as Bench Press, Squats (fantastic mass builder), Deadlifts.
Man bro, since you have never lifted and eaten like this before, you will be SHOCKED at how your body will transform in about 6 months......sooner even!
Good luck!
Skarn
It's better to burn out, than to fade away...