GSD's are good dogs, as vixie said don't allow your new pup to be rough with your smaller older dog, it's not fair, she may hurt him which will store up trouble from the future. I hope your pup has been bred from strong confident parents, if it has been done correctly you will be picking up a confident pup. Ensure you socialise her properly, so she doesn't react badly to new things. Step in quickly if you see situations arising with the two dogs.