Bwaha! This had me giggling, and "Oh, Luna!"-ing in a fondly amused way, all the way through. Her personality is absolutely spot on - it should possibly be disturbing how clearly I can see her acting just. Like. This. xD
And Dudley was actually pretty adorable. Which isn't exactly something I normally say, but I think you've had him mature very nicely!
I could go for more of Luna's, ah, observations on the Muggle world. Hee!