Are you sure she is a she? At 16 weeks none of my various pullets had large red combs and wattles like that. And at 16 weeks old that's how my Lavender Orpington rooster looks - he just started crowing the other day. It's hard to tell from such a far away photo, but the tail feathers look droppy and hackle feathers seem pointy.
But if she is definitely a she, and with that large a comb and red wattles at 16 weeks - she should be laying by now at 18 weeks old. So any day now would be my guess. However - depending on how much sunlight you are getting where she is - it may take longer for her to start.
Hope you get your answer soon :)