Hmm. Sounds like guarding behavior. Not so much protecting you but guarding you. In essence, letting everyone know that YOU belong to HER. She is growing up and claiming her territory - you!
I could, however, see my dogs getting a little jealous if I gave treats to another dog. I'm not a big dog park person but I have heard to never take treats inside the dog park.
Hopefully, someone who spends a lot of time at dog parks can give you some more advice so you can continue having fun there.
__________________  Mommy to Lucy, Ringo, and Matthew |