DD1 didn't crawl until 9 months and didn't walk until 14 months - I found that she wasn't a mover but she was a talker so maybe your DD is like mine and concentrating on developing in other areas. Babies do things in their own time and they will do things in different orders too so she will probably do other things earlier than this woman's child.
Thanks Nai - Funny you mention your DD being a talker, because my DD is very vocal, always chattering about something and practicing her Dada Mumma sounds!