it's annoying but she'll get there in the end.
If you think that it's because she forgets then you can ask her every now and then but not too often because it can just seem like nagging. My DS usually grabs hold of his crotch when he needs a pee but is distracted so if I see it I'll step in and remind him. If your daughter signals in any way that she needs the loo then try to remind her.