I try not to make a big deal out of it. Sometimes I say "ouch" but its more of because it actually hurt than to get them to let go, lol. Puppies are mouthy. Just keep redirecting.
Odd suggestion - Wear gloves when playing with her maybe? I wore some the first few weeks I had Steel while I was training him since his little teeth were making my thumb bleed.
You could try getting up and walking away, ignoring her to see if that makes a difference. Don't wait too long though, maybe 1 minute and go back to playing. See if she catches on. I feel she'll just chase you, nipping at your legs, though.
+ Kalbi CGC 6/21/2015
+ Blackthorn's Out of the Frying Pan NW1 ORT SEN SCN BCAT SIN RATN TKN (Katsu) 9/12/2017
+ Blackthorn's Skofnung BCAT TC CGC TKN RATI RATO (Steel) 07/23/2018