Still a pullet. Male sexlinks are almost all white/cream with brownish red feathers on their backs and sometimes on their wings. They also sprout huge combs and wattles at a very young age, as early as 6 weeks. You'd have seen that weeks and weeks ago, had it been a cockerel.
Telling the gender of sex-link chickens is pretty easy.
I was surprised to see someone asking the gender of one.