It will cause premature closure of the growth plates....stunting your growth. The odd thing about that, is when the growth plates are prematurley closed, some folks gets a small growth spurt that represents only a fraction of what they might have done.
It can alter your endocrine system in such a way that later in life you will need to administer exogenous hormones to be normal. Using Anabolic Androgenic Steroids (AAS) prior to physical maturity (endocrine system often doesn't mature until mid to late 20s) is not a very smart thing to do. you are toying with a system that is not complete, and if it doesn;t mature on its own, then it won't mature later and you are stuck with what you have. Later in life, that may very well result in the necessity to adiminister hormones for the rest of your life just to be normal.
I didn't start using until I was 29. I have never had a blood panel done after that first cycle that had my levels as high as they were prior. This includes a blood panel done over a year after completing pct. So yes, it can throw off your natural production, even more so because of your age.