What age is the redwall tv series for?

Anyone

I would say that both the books and the TV show are meant for older children (middle-schoolers), because the violence might be too scary for younger children, and teenagers and up might falsely believe that the series is for children because it's about talking animals.

Of course, it doesn't matter what age you are. If you want to watch it, then you can. I myself am a teenager and I am a fan of the Redwall series.