Just a warning -- she is not fully vaccinated and should not be WALKING in the neighborhood either. You are putting her at huge risk of parvo walking around the neighborhood not fully vaccinated.
A dog park and pet store are the worst places to take a timid dog. She will be bullied and over stimulated. It will not work out well.
My advice -- immediately STOP walking her. She's young, you are frightening her more and more, and you are on the quick trip to parvo land.
Find yourself a good private dog school. NOT petsmart or petco, like a real place that is indoors with good trainers. Once she is vaccinated fully, start with a puppy kindergarten. Training, socialization, and other dogs. Each week your trainer can suggest a couple appropriate outtings to build confidence. Keep going with obedience school - basic, intermediate, advanced. This builds socialization with people and dogs in a controlled environment and also confidence as she gains success. An agility 1 class also brings confidence as the dogs master the different obstacles.
Forcing a timid dog to "face her fears" does not work. Dogs don't understand "oh just get over it you are OK" like you can do with children.
Work with a trainer on confidence building appropriate activities and add more and more different experiences as she ages and can cope. For now, you can have people visit and maybe an adult fully vaccinated healthy well balanced dog visit. Have a different person come every day. Do things at home like different surfaces, climbing on things, different noises, riding around in the car, watching things from windows.
Please don't go walking her around the neighborhood not fully vaccinated and don't keep forcing her into really scary situations hoping exposure will be enough. It will only teach her the world is a very scary place.
Cara -- Central CA
+ Shay -- GSD
+Melody Rose & Cubby Shelties