This little one will be 3 weeks old tomorrow. It's unsexed, but we wanted to take a chance and see if we could end up with a pullet because the frizzle is just so darn cute! I was told that cochins were easy to sex early, but I don't have any others as a reference.
I can usually sex mine around 5 weeks. It's comb looks pretty prominent, but I have had hens that started out with big combs. Give it a little more time and update when its closer to 5 weeks.