We attended a Kindermusik demo and I think it REALLY depends on the teacher and class. There was only one other boy in our class, my LG was 10 months old and he was 18 months old... big difference at that age. LG wasnt even crawling properly and LB was running around and singing! You have to look around and find the right group for you!
We were still going to join, and I was hoping more kids would join, because there wouldnt be too much socialising if it was only 2 kids, but then LG got sick, then teacher was sick and so we never went back. Now that I am pregnant, I think we should do something just for LG, but I also dont know what. I liked the music part, because my LG just LOVES music, and her DH is into music and used to be in a band. So maybe I must wait and try a real music school sometime later?
Good luck!