I was a dark blonde and now have my grey (Really grey around the temples, some everywhere else) "blended." On the one hand, it looks really good, and you can't see the grow-out (I go in about every 12 weeks. If I wanted it always perfect, I would probably go in every 8) but it is so much time and expense at the hair-dressers. I have highlights, a smudged root, plus a scandi hair-line, so all the hair around my face is white, so the roots don't show. You can't tell if it is white or very light blond, so it works. But it is so so much effort.
Looking at your skin-tone, going blonde might not be right for you. Even if you have it toned quite cool, quickly it will pull back to warm. And, as you still have a lot of dark, you will probably then have roots, just a different kind of roots. Plus it's kind of hard on your hair, if the hair-dresser isn't super careful.
I would say, either learn to love it (It does look amazing) and balance it with some cool new clothes and some updated make-up, or go back to just a little lighter than your original color (with highlights, perhaps) but cool-toned, but also prepare to have your roots done fortnightly.
As it is now is REALLY lovely. But if you don't love it, change it. Just worried that blonde (particularly blonde that pulls warm) will wash you out and will feel odd if you've always been darker.