I am not exactly sure...I feel like I'm leaning towards pullet. If it develops more streamers and sickles it is probably a rooster, this is the easiest way to tell gender with silkies. Great pictures of this pretty bird!
How old? I would have said pullet till I saw the comb. It's not written in stone but pullets usually have a narrow comb and males have a hideous fat toad growing out of their head.