
As long as you have
both trained your dog from the word go and have set rules for discipline etc and have read all the books you can so you know the traits of your dog then you should be just fine :)
If one does seem a bit nervous of the other, make meeting short and sweet to begin with, walking past each other in the courtyard, sitting next to each other etc and then they will build a bond and be best friends and since they will both be so young that is a 100% bonus!! :)
Its no different to 2 dogs meeting in a park to play in terms of territory, staffords are no harder to get on with then any other dog, espicially at that younger age so your pup should be just fine :)
Might wanna drum in into your friend to train train train their puppy tho as a untrained stafford is a living nightmare for hyperness etc, but a well trained, well walked stafford is the most friendly playful dog in the world :)
Good luck with your new puppies!!!