I actually have 2 about the same age that look about the same. Mine are both girls. I'd agree with the boy/girl vote but i've had certain hens before whose combs simply grew faster than others. If you really want to know you can take them to a feed store and the owner could probably sex them. Otherwise, just go ahead, wait, and find out in a month.
That puts MPC at four mistakes for this one order and one request completely ignored.
We ordered 6 chicks and two have been roos so they are sexing at 72 2/3%
We requested no male packing peanuts and they sent one. If you want to include that in their sexing then it has been 61.1% sexing accuracy which is terrible.
A side view may be better. The one on the right appears to have some rump feathers starting to curl, which is a sign of roo. Could be a slow maturing rooster. Post more pics.