Lucy has one big problem - kids! I don't have kids, or know many people who do...therefore, she wasn't well socialized with kids as a pup. Now it's a 

roblem, since kids will often approach us on walks and ask to pet her (I love that they ask). She immediately gets tense when she sees a child and backs up. If they keep coming in our direction, she will bark. I think she is doing this b/c she is scared, but to the kids/parents she does sound pretty fierce. I never comfort her, and instead tell her to be quiet, after I politely tell the child/parent that she is working on getting used to kids and it isn't a good idea for them to pet her. She is fine passing adults or other dogs.
Sometimes she listens to me, mostly not, and continues to bark. Problem is, this may be self-reinforcing, since she was able to "scare the kids away with her barking".
Does she not trust me enough to listen to me? How can I help her to be less reactive to kids? I don't know any kids to practice with, and I certainly won't "practice" on someone else's kids!
I would appreciate advice...it's to the point where I dread seeing kids coming our way. Sorry for the long post...