A 17 year old already has sky-high testosterone levels! There is really no reason to try and boost them even higher at your age.
Men's T-levels peak out around age 17 - 25. If you take that stuff, it's possible that it could shut down your body's natural production of testosterone. I doubt that Novatest really works, but if it does and you do boost your T-levels to super-high levels then expect to experience severe acne, baldness, and possibly liver damage, and shrinking of your testicles.