IVE GOT A STAFFY AND SHES 6 MONTHS OLDWHAT AGE WILL SHE BE WHEN SHES FULLY GROWN

Depends entirely on the particular animal Guest.
Some will look well developed at a young age and some will take their time to fully develop- up to 2 and half years.

staffy's are usually mature by eighteen months. Of course there are exceptions as there is with any breed.

my staffy is nearly two and she is still growing her brother is as tall as her but his head is bigger  they have probably got about another 6 months or so to go till they are fully grown

At what age does a staffy stop growing height wise. I have a 5 month old staffy and he is about thirteen inches at the withers,