Figgy is another unbelievably clumsy cat - he rolls over and falls off things loads, suspect if I subjected him to an MRI (which I wouldn't, not for this) it'd show some very mild static (non changing) defect or injury in the motor cortex - like a human with dyspraxia. He's not ill, it's never changed or got worse or shown any sign of any problem at all, apart from occasional hilarity when he falls out of bed.
If you see any sign of any actual problem - including a bad fall, or if anything changes then absolutely straight to the vets, do not pass go or collect £200. If she's been like this for as long as you've known her, though? Unlikely to be anything significant. All creatures exist on a spectrum of ability, not just humans.