What I quoted above is actually a Tosfos Harosh. Tosfos does entertain the idea that a woman is allowed to judge. He also says that perhaps she was Shofetes Al Pi Hadibur, or that she didn’t judge on her own, rather she taught the Dayanim what to Pasken. Then he brings from a Yerushalmi that learns from a Passuk that she may not judge.
This is in Nida 50, the top Tosafos.