I agree to steer clear and especially at your age. You are not even done really growing yet at 19. Your natural hormones are working the way they should in nature. And believe me, you can go quite far natty, and probably (since you have little experiences with all this lifting yet) farther than you may ever think you could...!
Be patient with your progress, (I know it gets tough 'cause we all want to happen overnight) but the fun is working to get there. Stick to a solid sound routine centered around big compound exercises, eat well and enough, rest when you are supposed too and you can go very far with just hard work, focus and determination.