I don't think it is too early... in fact I am hoping to start DD on a potty soon, in the mornings when we get out of bed she comes into the bathroom with me and will squat and either do a wee or a poo in her nappy, she then wipes her bum (well her nappy!!) with the square of toilet paper I give her to entertain herself while I do my business and then she wants to put it into the toilet. I am not sure about fully TT her but it seems to be that this would be a good time to sit her onto the potty and see what happens.