Hi!
I never found a shade for C girls (Olive and yellow skin), #125 is okay for NC30, but nothing seems to be made for olive skin.
If you still want to try it, buy a shade closer to your skintone, and mix it with a green pigment. That's what I did with my #120 (Too pink when I wear it alone), I mix it with True Chartreuse.
True Chartreuse may work for you, but you may need a darker green if you skintone is really dark (C40 can be very dark, but I use it in summer and I doesn't look like I was a C40, know what I mean? It really depends on who wear it, I think.)