My german sherpard dog is already 10 months old. She is still very shy with other dogs. Even a very small size dog can chase her. If other dogs approach her aggresively, she submited immediately. I would like her to play with other dogs happily with confidence. Most dogs she met in off-leash park were very nice (not as aggressive as she thought).  Please give me some tips on how to train her to be confident like a gsd should be.