Yes, on "D.W.'s Perfect Wish" she turned 5 March 1st. But if Arthur's birth date was the same in the episode "Arthur's Birthday" as it was in the book Arthur's Birthday (November 25th), there's a contradiction.

Also, I've said this before, the order that the episodes first aired aren't necessarily the order that the stories take place. Remember, in "Revenge of the Chip," the newspaper article said that D.W. was 5, and that episode aired before "D.W's Perfect Wish." I did think that for "Return of the Snowball" D.W. should have been 5 not 4.

I have a question. Do we know how many times on the show someone said D.W. was 4 and how many times someone said she was 5?