I highly recommend enrolling her in a puppy class immediately. The socialization window starts to close by 12wks of age. Don't force her to interact with dogs or people, but just let her observe in a place she feels safe. A good puppy class should be set up where the puppies get to play and meet the other puppies and people, but the shyer ones can just watch on the outsides. Usually the shyer pups get braver and braver every week!
You could even take her to a pet store to meet other people. Have people try and give her treats. If she's too scared to take a treat, you can have the person toss the treat to her.
But try not to drag her to things she's afraid of. Crouching down, walking backwards, sweet talking her might be slower but then it's her choice. If you have to you can pick her up to bring her somewhere, but when she's greeting people and dogs she should be on the floor and not shoved at them. Make every experience a positive one!
I wouldn't be overly concerned, but you do need to act quickly so you can take advantage of the socialization period. Anything puppies meet (and have a good experience with) in the first 12-16wks of their lives is seen as normal. If they never saw men, or someone wearing a hat, etc in this timeframe then they will be naturally cautious when seeing men and hats when older.
