Hi! I have two Silver Laced Wyandottes and they are both hens. I asked this same question when I noticed only one of mine had a rose comb. It turns out that the hen with the single comb was a "hatchery mistake". Sometimes a SLW hen will end up with a single comb. Yours looks like a pullet to me. She looks very similar to my hen. ~ChickenFarmer03
SLW pullets have less contrasting colors. The males are deeper black and contrasting white lacing. On pullets, the patterns are less contrasting until quite a bit later, making one wonder where the lacing is.
Also, the comb is definitely redder than the pullet's.
Here are two of my 3. The two boys went to freezer camp a few weeks back. These pics were taken at roughly the same age as OP. The cockerel was crowing by then and quite well. In fact I still miss his crow as the two boys I kept (Bhrama and Jersey Giant) still aren't as loud and they're almost 6 months. The pullet looks like the OP's. Of course she's much redder now and will hopefully give me an egg any day now!