So at baby girls 4mo appointment her pediatrician said he wanted us to work on her sitting up on her own and by her 6 mo appointment he said she should be able to do that? I know everyone on here says all babies do things in their own time she does great as a supported sitter (in her high chair, her sit me up, sitting between my legs with her back against my tummy) but how do I 'work' on getting her to sit up on her own?