It does depend on the breed as to how fast they mature and grow out of puppy antics. Smaller dogs seem to mature faster than bigger ones. However, environment plays a part in it too. Obedience training, proper socialization skills and physical activity all have a part in how they mature. A dog left to it's own devices day in and day out will probably be destructive and "WILD" a lot longer than a trained, physically active, properly socialized dog.

Labs in general usually are not considered adult dogs until around two years of age, even though they may be full grown a year before this.