Species Identification

I bought this African cichlid today and at first I thought it was a female kenyi, but once I got it home I done my research and it says that all kenyi are born blue and the male's will eventually go yellow with darker vertical bars, Notice that mine has started to show signs of yellow on his/her fins. Could this mean it is a male? Ultimately I would like a male as I have 2 other females.

 

Several of mine started out blue and ended up yellow so it's very posable you have a male

How big is he?

He's around 2". I read somewhere that they gain their adult colours at around 4" is this correct?