She is 4 months old. She may mature and be more confident and not feel like she needs to bark at everything. Tell her "No." and walk on. Do not hit her, do not yell. Just move on. Take her to classes, and maybe start some puppy agility with her. Lots of praise and lots of treats when she does good. She will gain trust in you and confidence in herself, and it may take several months, but you will learn each other, to the point where you will be able to say to her before she barks, "It's just a man, leave it." And she will understand that you are not worried, and she will have confidence in you to protect her.
Obedience training with praise and treats. Agility training, fun, fun, fun, praise and treats. And time.
Don't flood her with socialization experiences. Back off with having everyone meet and pet her. Take her out and learn at what point she starts to feel insecure and adjust your direction before she does. After a couple of weeks of training, see if you can move closer before she becomes insecure, 2 steps closer, good. That is your new mark.
With continued training and praise, in another 7 years, she will be the best dog anywhere. (But you should see improvement a lot sooner than that.)
Bear Cub, Hepsi-Pepsi
Cujo2, Karma Chameleon
Ramona the Pest, Kojak -- who loves you baby?
Tiny Tinnie, Susie's Uzzi, Kaiah -- The Baby Monster.