Was this the nittiest player ever?

Playing live $1-2. Hand AcAh. Pos UTG. Stack around $250.

I open to $10. and per usual the pot goes MW. 4 in the hand $41 in the pot.

F:T42 rainbow.
bb X, I bet $20, 2 calls. btn and bb. pot $101

T:5

x, $50, fold, call Pot$201

R:6
x, I jam.
BB starts cussing. and says "damn it. I flopped a set but I just feel like you have a 3 here." after a few minutes she folds and I'm thinking to myself "How in the hell do you fold a set here the way this hand played out?"