When I was about five or six years old my parents gave me a basic origami kit. All the instructions were in Japanese, but the diagrams were simple enough that I was able to figure most of them out.
A few years later I saw this book — and being a paleontology-obsessed little kid I had to have it. The Pteranodon model diagrams were the longest and most complicated in the whole book, and it took me a long time to learn how to make it. I think I was twelve when I finally managed to complete it properly for the first time.
I can fold it entirely from memory now. :3
(Pteranodon model originally designed by Fumiaki Kawahata, folded here by myself)