grey or black city

I'm in the same boat, for my 25th birthday I want to treat myself to my first city bbag but I don't know if I want grey or black as well for the same reasons. My birthday's in march so I have some time, but I'm not sure if I should put myself of the waiting list for the anthracite or just buy the black in march.
 
I'm thinking since you already have a black Balenciaga you should go for grey?
I've a Greige City and it's such a pretty and versatile colour.
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