I've taken a couple of writing classes from Gotham Writers. Children's Writing I and II. They were very helpful. There are weekly exercises that an instructor will share feedback on, plus you submit your story twice (pretty sure it's twice!) during each class for class and teacher feedback. If you've done a lot of self-study, Children's Writing II may be better for you, as the lecture topics build.
It was helpful to me to break it down by element of craft. I also did meet some women who I've continued to critique with for the past 2.5 years now.
I think that part depends a lot on the participants and how much effort they make to get to know their classmates.
Several other writers on Inked Voices (my business) have taken Gotham classes and gotten a lot out of them. What children's genre are you writing? PB, ER, MG, YA? If any other thoughts come to mind based on your genre, I will share.