My dog is 5 1/2 months old and has similar issues. She is very interested in other dogs, and we took her to some dog parks when she was in the 4 month range. She would just hide in between our legs, but follow the dogs around if they weren't looking at her. If they tried to play with her, she would retreat back between our legs and cower. Now she barks very aggressively at dogs from a distance but when they get within about 10 feet she stays close and quiet. We had to wait a a little bit on socialization because of shots, and we live in a rural area that doesn't have puppy kindergarten classes. She is good with dogs when she spends time with them, but is still pretty bad at new introductions.