Have you felt between her pelvic bones to see if they are spreading out? As far as I know, that doesn't happen with roosters, just hens getting ready to lay.
Looks like a pullet about ready to lay to me. My BA is about a month younger than yours and doesn't have the impressive comb/wattles but she does have a few soft, rounded short feathers (and all of her feathers look iridescent in the sunlight) falling on either side of her back right before her...