
I would suggest taking her to training classes. The more people and dogs she sees in a controlled way the less excited she will become, if you act calmly, firmly insist on her sitting and geeting calmly with lots of quiet praise. speak to her in a low voice, very slowly and calmly. Also try to keep your body movements slow so as not to excite her. When you pet yher make the pats/strokes very slow and soothing!
This is something that she will grow out of if you do the training, she sounds a beautifully confident and friendly girl. Many baby puppies especially bitchews will wee with excitement or appeasement. Try to ignore it and do things to keep her calm, if you get cross she will do it more, as it is a submissive gesture.
If she is a Standard or Large Minature a Gentle Leader Head Collar would give you more control.