When will my jack russle cross calm down?

don't be surprised by jack Russel and this Question im asking because it sounds silly because jack Russel's are existed and hyper dogs!! but She is crossed with a yorkie her mum was a Yorkshire terrier and her dad was a jack Russel he is medium-sized noting to big at all,she was the runt of the litter(smallest out of them all) SO WHEN WILL SHE CALM DOWN ?? she is 6 months