Baby not flipping around

So the first picture is my 15 week ultrasound… the second picture is from today at 18 weeks 5 days. It’s been nearly 4 weeks and baby appears to be in the same position she was at 15 weeks. I have an anterior placenta so if she has been rolling and flipping around, I certainly can’t tell. I have no abnormalities of my uterus and everything came back fine on baby’s end… Is it normal for babies to stay in the same position for this long?? Am I worrying for nothing? Both ultrasounds she’s head down with her feet curving up my side a bit. She kicks and is active throughout the day, but no clue if any of those movements have been rolling.