Mine would have to be Sailor Moon or Pokemon when I was 5. This was before I knew it was Anime. My parents reaction when I was watching as a kid was priceless XD !!!
My first Anime was Dragonball at around the age 3 - 4. (infact the very first memory I have is of myself laughing at the TV sceen because Goku said to Krillin "but Krillin you don't even have a nose!")