From the
Acromegaly article on Wikipedia:
"Because of its pathogenesis and
slow progression, it is hard to diagnose in the early stages and is frequently missed for years until changes in external features, especially of the face, become noticeable."
Bolding and underlining are mine.
Basically you are asking if you can give yourself cirrhosis of the liver by going out on a Friday night and getting drunk off your ass. Just like it takes years of alcohol abuse to cause cirrhosis, my swag (scientific-wild-ass-guess) is that you will most likely need years of excessive growth hormone to cause acromegaly.
And because HGH can be $1500 or more per month, you probably won't make it past (I'll be generous) 6 months. At 19, unless you're a trust fund kid with rich parents, you won't make it past 3 weeks. That will probably leave you with a headache, moobs (that's man boobs) and no money.
But let's assume you have the cash, now you need to find a doctor willing to lose his medical license to prescribe you HGH. Of course he's going to get you to run tests, so he'll have to be in on your plan. All of a sudden the price just went up because no doctor, making $250k a year, is going to jeopardize his entire career for maybe $20k a year.
So what can you do? You could buy HGH over the internet ... from some underground lab in Mexico or Vietnam. Let's assume you can get the stuff through customs for two years. Because acromegaly is a slow progressing condition, in two years and $50k later you realize that the HGH you bought was bunk. So now you are broke and still only 5'8" tall.
There's a lot of assumption in there, but it sounds like a plan.