lol . . .

I don't think it's mean if you tell her that she talks a lot . . . Maybe if you told her that she talks too much it would be mean.

I guess she's not really responsible for a lot of her behaviour at this stage in her life, so it would be up to you to monitor this kind of behaviour instead of lashing out at her. So in that sense it would be wrong to criticize her.

If you are concerned, then maybe bring her up with your therapist or even discuss it with Doc John in one of the hosted chats here.