You're little girl is gorgeous. So glad she's off that lead.
You'll get a lot of good advice from the people here and I also suggest searching through the puppy section for socializing tips.
What I suggest is that you seek out the help of your friends & family. If any of them have kids that have experience with dogs, invite them over. Its important that you don't invite kids over that have fear of dogs
Have the kids just hang out with treats and let your girl come to them on her terms.