I have olive skin as well and i think the light/medium color is perfect for my skin even with a slight tan on my face. I was to afraid of trying the med/dark in fear it would be way too dark.
I use Light/Med and I am med/olive(oily skin)and it is a little light for me. BUT, I warm it up with Bare Minerals Matte in Golden Med. I got a sample before I read it had pink undertones, it would have scared me, but surprisingly enough it did not show up on my skin that way. Give it a try, I love the product, it has much more of oil control than Smashbox bb cream light/med. Both are great, but for the summer, I will opt to use Dr.Brandt. Hope this helps.