Very normal. I didn't feel my first until about 18 weeks, and my second and third pregnancies I have felt the baby between weeks 16 and 17. It all depends on the positioning of your baby, and the placenta. I know I've had a posterior placenta (placenta on the back side of the uterus) every time, so I'm likely to feel baby earlier than someone who has an anterior placenta (placenta on the front, cushioning you from feeling anything). That said, I'm 19 weeks now and if baby turns around facing my back, I can't feel him at all still! They're so tiny still at 16 weeks that they move all over the place.