Possibly thinning due to family history
I don't think you're thinning. You just may be prematurely concerned due to your family history. If you're concerned, though, it doesn't hurt to jump on minoxidil / nizoral right now — hold off on Propecia for now, as you're only 18 and may still be...
Update Today?
Absolutely great regrowth, certainly inspiring. I am currently in the same boat as your were at the beginning (Norwood 2, only receding at the hairline). I started my regimen of the BIG 3 a week ago. What is your hairline like today, has the treatment prevailed in the long run