“Chein: See above. If you have a conflicting source, quote it.”
His source is the Magen Avraham. But it is a Daat Yachid. And to quote it as if it is the halachah is to distort Torah. Among those who differ:
Rambam
Tur
Shulchan Aruch
Rav Chaim of Brisk
Mishnah Berurah
Aruch HaShulchan
“Women/girls are potur of mitzvos shehazeman grama”
Rambam and Shulchan Aruch say that tefillah is NOT a mitzvah asei shehazeman grama!