Well, props for you on not going blonde. I'm a hairdresser and will even speak from personal experience - going blonde from dark (ESPECIALLY black), pretty much fries your hair. If you thought it's frizzy its not even imaginable how frizzy it would be after going blonde.
Turquoise would be nice though. Have you thought of maybe keeping a bunch of dark and doing most of your fringe and a few chunky pieces through the sides? It'll brighten it up and add some life to your color.