I bought 4 BR pullets and one turned out to be a roo. We call him "HENry". We noticed early on that his contrasting colors were brighter and he developed a comb earlier and it was redder. About the time his wattles really started coming in, he started having "roo" feathers develop along his tail and saddle. You may be in for the same treat as me, but at 11 weeks mine had a more prominent red comb.
Do you have siblings to compare to? That was our advantage, but I've found that most chickens develop in their own way and their own pace. It looks like he's developing roo feathers along his saddle and tail, but the comb/wattle seem underdeveloped for a roo at that age.
That's a male--no pullet has those skinny, shiny saddle feathers, but the comb is odd. Where did you get this bird? Is that a single comb or a rose comb? The angle makes it hard to see the comb. The body type seems very lean for a BR to me, so I'd say male and not pure BR, or maybe not BR at all, really, just going on that one picture. Could you get a body shot of the bird standing, then a comb shot?