Baby guppy question

[Fishies86]

When do baby male guppies develop their gonopodiums? I've got some babies that are 3 months old. There are also two other batches that are one and two months old, and some that were born the other day. The 2 month old ones are developing colour, though the 3 months stayed the same colour as when they were born. There are a few that seem to have a small gravid spot, so these must be female. The others don't seem to be obviously male, but I thought they'd have changed by now. Are they just late developers, as shown by the lack of colour change?

 

[pendergraft2111]

Females mature at about 3 months of age or sooner in a warmer tank. Males mature somewhat sooner and will develop after several weeks. It may be hard to tell but if you are going for a certain trait you may want to separate the males out as soon as possible