After 25 years of entertaining kids on PBS, the network is bidding adieu to Arthur, a beloved children's television series based on the books by Marc Brown. While many people are mourning the loss or celebrating the series' title as longest running children's program, the whole thing is mostly making me feel really, really old. As someone who was raised by a mother who restricted our television viewing to public channels, Arthur was a huge part of my childhood , starting from when the first epi…