You probably shouldn't do it unless you consult with your doctor first, it could really fuck you up. And you should probably only take it if you actually plan on working out, not good to take it while sedentary.
If you have low testosterone levels it's probably not the end of the world to take it if you don't work out, but you're probably better off taking something like Tribulus Terrestris, which may or may not restore your body's natural testosterone levels. I'm pretty sure taking testosterone by itself (real or synthetic) reduces your body's ability to create testosterone by itself, so it's pretty dumb to do if you're otherwise healthy, below 30, and have no need for the extra performance.
Honestly though, unless you've been diagnosed with low testosterone by a real doctor, there's seriously no reason a 17 year old should fuck with anabolics at all. Depending on the type of supplement, you could grow tits, break out with heinous acne or other skin conditions, as well as the potential social effects. If you're 17 years old and healthy and you want to get huge, diet and working out until you shit yourself will probably have a much more profound effect. If you're 17 years old, otherwise healthy, and aren't trying to get huge, I can't fathom why you'd inject yourself with this shit.