Interesting, if natural henna can add color to darker hair, why can't the "miracles" of chemistry? Maybe there is a way to impart blue highlights without bleaching... if so, then I vote yay for the blue. Your hair is absolutely gorgeous as is from what I've been able to see, and it doesn't need color improvement. But, if it's something that you really want to try -- and are prepared to live with it for a while if it doesn't come out to your liking, or are ready to dye it to your natural color -- then do it, why not, we only live once! Well, maybe more than once, but just once in our current bodies.