I think she's just being timid, being that it's her first time. Coco was very much like that. She was shaking, belly up, and taking cover. By the next couple of times, she was a completely different pup. Now, COCO is the boss of that little dog park. She loves it there. I would rather her be socialized and have fun and be a little slobbered up, then not be socialized at all. It's a park afterall, and no one expects to come back clean after that.
