New miniature pinscher behavioral problem

Hey guys! I just got a 3 year old min pin from a friendly household. They were keeping her temporarily since his first owners couldn’t take care of her any more and were having her up for adoption. Since I was looking for a dog to adopt this friendly household suggested I take her home with me for a few days to see if we “connect” and if so adopt her. So it’s day number two and I’m a little troubled about the matter. In general “Nike” seems like a good dog. She is potty trained is rather quite( sometimes she barks at the doorbell sometimes she does not). But the problem is when she gets out of the house. Aside from the fact that she pulls a lot, whenever she sees a dog she starts whining and pulling to get close to it as if excited but then starts barking and I can’t really tell if it’s excitedness or aggression and this whole situation kind of stresses me out because you don’t really enjoy a walk like that. Any suggestions? Why could she be doing that? How to deal with it?