First off, grats on the impressive numbers.
You had asked whats wrong with doing steroids at your age.
If you read these forums and many others, you will see the panic, frustration and fear the results when steroids are taken without proper research and body development.
Here is a recent post from a kid who developed gyno.
Every month or so we see these posts and just shake our head and offer advice.
Please understand, your body is developing just as fast and if not faster than any amount of steriods will do.
Your actions over the next few years will have a lasting impact on your hormones for the rest of your life. Let your body run its course, do the basics, lift heavy, train hard and eat a ton of good food and you will no doubt be far better off than messing around right now.
If you eat, lift, train hard, you will be massive and build a GREAT base for when you are in your twenties if you want to bring it to the next level.
Enjoy the free ride of free test.
Keep us posted on the numbers and progress though.