neudmama
Sof davar gave a good answer. I might add that it could be that some girls don’t know they have a Chiyuv to daven. I think they should be told in a nice way that they have a chiyuv to daven. Also, I’m pretty sure they must daven before zman tefillah is over as well. To me, it looks like girls view Shabbos as a vacation and therefore sleep late and take it easy.