My baby laying with her head at placenta

Christina
The first ultrasound was at 18 weeks. She was laying at my placenta then. Last two ultrasounds are at 22 weeks. There she is again at the placenta. I plan to ask my OBGYN next time I go.. But is this something I should worry about? I didn't think anything of it up until the other day when someone asked me if it was normal. I feel her kicking and moving regularly.