If you're at all concerned, get her fitted with a muzzle, and never let her off the leash in public places until you are sure she is ok.
Also, as with any dog breed, never ever leave her unattended with children or babies, no matter even if she does turn out to be a good temperament.
The RSPCA here have animal behaviourists who you can get help and advice from - maybe your SPCA has a similar service? Try get her into puppy walking/training classes too if there are any - your SPCA or vet should be able to let you know about availability.
Finally don't be nervous when around her, especially when you're walking her, because she will detect your fear and will be more likely to attack others in order to defend the pack - ie you! It makes sense when you think of it like that! Basically, she needs to know you're in charge and you do the protecting, then she'll feel safe.
Sometimes you just gotta think like a dog to get the answers lol!
Good luck and let us know how you get on