maybe she's scared of the bath, rather than water.

is she able to talk, to explain what's wrong?

my DS has started to explain things to me, so when he chucks a tantrum. I give him a hug and ask what's wrong? And he tries his best to tell me

otherwise, I'd just let her swim in the pool everyday, if it's a little one, add bubbles etc, like the bath and see if that helps....