The one you're holding in the very first picture, yeah. That's a cockerel. Brahmas are slow to develop. Pullets won't start turning pink in the comb until about 5 months old.
At this age the back feathers are the easiest to spot male/female feathering.
Here are two pullets. Look closely at the shape of their back feathers. They are broad and rounded, like the feathers over the rest of their bodies.
This photo shows a black pullet up front, and a cockerel in the...
The bird on the far left is male. He's got the 'rooster' red shoulders, the bright red comb, the long, thin, pointed back feathers. Now, look at your chicks. If the comb matches in color (not shape, cause you have a few different comb-types), you have a boy. If the shade of red on the...