Every dog is different, they are individuals, their personalities are different and they learn differently, but it is always a good idea to have formal training for young dogs. The sooner you start the better. When puppies leave their litter, they need a new family- that will be you. This includes providing them with food, water, shelter, love and education. Under the age of 6 months old, they are ready to absorb as much information about the world as they can, which means you can teach her everything you find necessary, so she can become the family companion you had in mind when you decided to get her.
Don't think of training as something you have to do when there is already a problem that you have to resolve. Early training and socialization is the best way to prevent behavioral issues that might occur later on and could become gradually more difficult to deal with as your dog gets older. I also look at training as a way of communicating with your dog: you learn to read her body language, respond accordingly and teach her your language (signs and cues). Training is also a wonderful opportunity for you and your dog to bond, it enhances and enriches the friendship which will help you build a stronger relationship. By finding a good trainer who can show you how to communicate with your puppy you are making sure that she reaches her full potential.
My puppy program covers basic obedience cues (like sit, down, come when called, potty training, etc.) and addresses behaviors like jumping on people, chewing, barking, or anything you are struggling with. At a young age it is also very important to properly socialize your puppy, so she can become a well balanced adult. Socialization period in dogs starts around 4 weeks and ends around 6 months of age, so we only have this short period of time to socialize our dogs.
If you are thinking about what kind of training method you should use, please always consider science based, kind, reinforcing methods, like clicker training. There is a lot of research that shows reward based training is actually working better than punishment based training.