. They are two different dojos, but they have the same teacher, Oğuzhan Başkurt, who is a quite dynamic teacher and moreover a friendly and nice person. As one of these is a university club and the other derived from it, the majority of members are young men, but there are also some women and older guys training, so if you don't belong to the young man category you won't feel excluded (I don't, either...).
I go to Turkey every summer for two months, and I always train there as a regular member.
You will find their training hours on the respective websites, and also contact addresses. And as many of the members are students, you'd normally get through with English.
If you are a 6th kyu, colour issues shouldn't be a problem - but in many Turkish dojos they don't have the colour code. You are just white until you get brown...and they pronounce the Japanese names a slight bit different from what I'm used to. But not so differently that you wouldn't understand.
There is also another dojo, Sakura dojo of the Haliç University. I never trained there, but they came over one day with a bunch of students plus the teacher to attend a Tissier seminar, so I trained with them just for the pleasure of speaking Turkish during an aikido seminar in Belgium and found them rather nice. You'd find their dojo on facebook or if you just put "Sakura dojo istanbul" or something like this in google.
All dojos I mentioned are in central parts of European Istanbul; in fact the aikimode dojo is some steps away from the Osmanbey metro station.
Wish you much fun in Istanbul!