2 of my friends' babies just SAT until they were 12 months old, not moving at all, and they both turned out fine, crawling at 12 months, walking around 15 months. So I wouldn't worry unless she is nearing 13 months and still not moving around in any way. The milestone chart from our mother -baby clinic also says that 12 months is the 'watch out' age for not moving so you've got a couple of months yet.
I walked early as a baby and my husband walked late and he is much more athletic than me!