You will ruin your body taking steroids at 18. Consider using some lower potency testosterone supplements. if you're adamant about it. Lift heavy, eat like a pig, sleep like a bear, and use proper dietary supplements for 3 years. Then when you have built a decent base for yourself by age 20-21, only then should you consider steroids, otherwise you are going to throw your hormone levels off for the rest of your life and possibly screw up your ligaments, tendons, and joints.
