I'm an out-of-shape 3.0 47yo man and I use racquets over 12 oz. The way I see it (in general) player racquets are 12 oz. and up; medium weight racquets are from 11 to 12 oz.; and anything below that is light and can be pushed around easily. And I'm playing at a low level.
I strongly recommend getting 4 demos from TW for $20 to cover shipping both ways. She will see for herself how much more solid contact she will make (and with manuverability) by going up an ounce. The Hammer is not a manuverable racquet and it ushered in a generation that sticks to the baseline.