I personally was physically active within days of giving birth, including horseback riding. I see no problem with light riding a mare two weeks after giving birth. Light riding defined as mostly walking with a little bit of trotting for less than a half hour of total work and no more than twice a week. She would do more in the pasture by herself. Baby still needs frequent nursing so any work should have frequent breaks to allow her to nurse, which also gives her body time to rest from any physical exertion and that time would also add into her total work time. Every mare is different, she will let you know how much she can do if you listen to her body language, IMO.
Even though she may have a new baby though, that gives no excuse for lack of respect, IMO. If you are letting her get away with pushing you around and not listening, it will probably only get worse. She is a smart girl, it won't take much to get her to listen once you decide that is what you want to focus on.