Just let her do what she wants to do when she wants to do it. It isn't important whether they sit before they crawl or vice versa. Just nod and smile and do what the two of you do - enjoy just being who you are. We can get very worried by what others say especially when they are supposed to be experts and when it is conflicting advice it's even worse. Not all babies crawl. All babies will need to sit unsupported at some stage (kind of hard to do grown up things if you can't!). Don't push either, just encourage achievement in whatever direction it happened.