i wouldn't worry too much, unless she seems overly exhausted and isn't feeding well. but you said she seems happy and is feeding great, so don't stress. i never use that charts, even when my kids were babies. i mean, are you and your DH average sized? not to be rude, but me and DH are kind of little people, and my kids are the same, i'm constantly joking they have hollow bones cause they eat so much but are so little! and me and DH were little as babies well. trust your instincts, i'm sure she's fine