Don't waste so much time on football. Very few kids who make it such a big part of their life ever have much to show for it once they become adults. Except for bad knees and shoulders.
Don't fight your sense of patriotism-surrender to it. You'll feel better as you grow older (and probably will have contributed more).
Make your heroes people who always put their country and/or friends first.
Go for something basic with your first handgun. A Smith & Wesson revolver. A Colt 1911. Stay away from anything saying Ultra, Tactical, Maxi, Mega, Special Edition, or Uber. Become proficient with it before you buy your next one.
If you never hunted or served in the military, seek out someone who can teach you how to shoot a rifle. Do it while as young as possible, while your eyesight is as good as it will ever be.
Read gun magazines in the library, or online. Before you even think about spending money on one, ask yourself how much ammo that money will buy.
After you've acquired a rifle, shotgun, and a handgun, and feel proficient with them, start saving for some professional training. Not another weapon.
No junk. Ever. Save for quality, even (and especially) if it means you have to sacrifice quantity.
Women? Be careful here. Meet their family if you find one you're at all serious about. Good looks are always great, but don't discount the ones that can have a great laugh with you and allow you to be yourself. Be careful how you treat them. You'll find this hard to believe, but they're someone's daughter. That will remain pretty meaningless, until you find yourself the father of a daughter or two.
Be serious about school. The way your education will impact your life (in so many different ways) in later years will astound you. Don't think you can always go back to finish a particular course of study. Get it done right the first time, while you're there. geegee