You're never too young to get into some older anime. I've actually done a few Retro Reviews of anime that came out before my time and found some absolute gems.
But yeah, Mononoke is an absolute classic. That movie has long proved it holds up to the test of time, every generation of anime fan seems to love that one.
Oh yeah,I have seen older animes, but I can't remember them as good as the
2000's ones.
Also, I have to search and download for free so I can't get all of them