I started watching anime when I was 7, as of most 20 year olds, and the first anime that I started watching is also predictable, Dragon Ball-Z.
The first anime that I completed was Love Hina, I was about 10, or 11 at that time, Love Hina was also the first anime I've seen in Japanese with subs.
By the time I turned 17 I owned my first anime box set My-HiME, that's right, I got volume seven as soon as it hit the shelf. *grin*
Now I am 20 years old, and I need a new shelf, by the 3rd year of collecting anime.
I am sorry for not giving details on my anime list, but I am not so sure about many of them, it's too much to remember...