*sigh*
I will not condone a cycle that young, but I'll make some suggestions for your safety, cuz... I'm gettin worn down by the lack of patience people have these days.
1) Make sure (via bloodwork) your endocrine system has settled into normal (i.e. get some work now, in 6 months, and when you turn 20).
2) Make sure (usually only by x-rays) that your growth plates have fused and you are done growing.
3) Understand that once you go to the "darkside" trainging/gaining/cutting naturally will feel like a waste of your time.
4) Cycles are expensive, especially once you add up the cost of the extra/proper food, support supps/anacillaries (that you might not even use), and a proper solid PCT.
#1 is the most important, because if your endocrine system hasn't normalized, it could decide to normalize when your natural outputs are nonexistant during your cycle, and this can lead to all sortsa trouble sooner rather than later.
#2 is also important.
I had bloodwork done for a year prior to my first cycle, and an x-ray done (besdies the fact I hadn't grown an inch since I was 12-14 (can't remember exactly) to ensure I wasn't going to screw myself up long-term. It wasn't cheap, but it was well worth it for the peace of mind.
ManBeast