Trip to Athens and Istanbul?

First of all, sorry for neglecting the blogosphere for so long… I’ve been completely overworked and overstressed… no excuse, I know. Now getting down to business..

I have a few friends who would like to go to Greece this summer, and they found a great deal on a trip that includes Athens… and Istanbul. I’ll admit that there are many things in Istanbul that I’ve always wanted to see, but…
I’m an American girl, blonde, somewhat overweight – in otherwords, obviously western. I’m not stupid, but the only languages I speak are English, Spanish, and Italian. I’m also not loaded and I hear things become insanely expensive over there, as they jack up prices for Americans.
My question to you all:
Should I be worried?