Dear 16 year old me:
Write. Really. All else be damned, pound the keys of that old Royal typewriter until they bleed. Other people can define success as they want to, but you have a voice and it should be heard.
And while we're at it, take that old Argus, and the black and white film that Harry gives you, and go take those photographs. Maybe you can't draw a straight line with a ruler, but you do have an eye for composition and form, and those tiny details you see? They work.
Laugh, a lot. They're right. Laughing makes for much better wrinkles than frowning, and more people are willing to laugh with you than are willing to sit around stewing in a pool of angst.
And lastly, you don't have to marry them. Sleep with them, sure. You can even live with them. But dear sweet gods on hairy pogo sticks, try to remember that you are a unique and free-spirited person who does not flourish in captivity. Unless he's willing to treat the ring on your finger as something other than a noose around your neck, RUN AWAY.
Love yourself,
Me, aged 55