I started feeling dull movement at 19 weeks now 22 weeks. I, too, have anterior placenta which is right in front of my stomach. If my son wasn't in breech position, I probably wouldn't be able to feel him. Usually feel his feet on my bladder.
I felt my baby kick at exactly 18 weeks:)
I started to feel my baby at 24 weeks but her placenta is in the front so it blocks alot of her movement so im 31 weeks tomorrow and i still dont feel much unless she goes around the placenta to hit or kick me. I never feel anything in the middle of my stomach always on the side. Its different for everyone and it depends if you are a first time mom and where the plqcenta is.
Between 18-24 weeks is normal. I felt my baby move at 16 weeks 4 days but its different for everyone. A friend of mine didn't feel her baby move until almost 22 weeks.