I watched Inuyasha when I was 4 with my sister, I watched all the episodes and really enjoyed watching it. There where many episodes and took some time to watch, I finished watching Inuyasha when I turned 7 XD, I never thought there would be Yashahime: Princess Half-Demon. When I found out about this show I was really excited to watch!! :D. I actually thought the series will end in the last episode of Inuyasha, and never knew their children will continue the series. It's good that I watched Inuyasha or else I would not understand a thing in Yashahime: Princess Half-Demon. I really recommend you to finish watching Inuyasha first then Yashahime.. :))