Racket's are cheap here on TW.
You can get her a YoutekRadHeadMid+ for 39 bucks used, low 11 oz, 62 flex, 98 head size for her to try.
In the end, the decision is up to her and her game. Long loopy swings can use lighter rackets, while more direct swings need more mass to hit hard.
Heck, you can buy her a NEW Dunlop300Lite for 70 bucks, 9.8 oz and colors to die for.