why is my puppy so shy?

Question
We have been taking our 6 month old cocker spaniel, Daisy, to puppy training classes recently. She is fine with the training part but she seems to want nothing to do with the other dogs! In class there is a short playtime in which the puppies can get to know eachother and play around. Daisy sniffs around and might sniff some of the dogs, but otherwise she is really shy and never really wants to play with the other any of the other puppies! The instructor suggested that we enroll her in a few doggie daycare sessions so that she can get more comfortable around dogs. What do you think?!

Answer
Much of a dog's personality is determined genetically, and the first 12 weeks of life strongly influences the rest.  It could be genetic or due to too little contact with other dogs before 12 weeks.  I would try the trainer's suggestion.  Whether the problem comes from genetics or socialization, in time, you may be able to improve it.