Growling isn't necessarily aggression, they growl when they play. So in your case I wouldn't worry about it.
If you would prefer your dog not to growl it's OK to stop play, that will be plenty. But never scold or punish a dog for growling, growling when not in play is them telling you they don't like something. If you punish them for growling, they'll switch to using biting to tell you they don't like something.
But again in your case, growling is probably just your dog having fun. Some dogs are more vocal than others.