J.J.
Relax! She is only 4! As a mom of an 18 year old with autism, I do not think that the "regression" in skills you are describing are assoicated with that.
Focus on her having good manners, making friends, playing cooperatively rather than the academic skills. You want to have a child who loves learning, not one who is the earliest to learn things. Developmentally she sounds like she's way ahead of the game so ease off on the pushing the "skills" and work on the softer, more subtle skills that will carry her through so many situations in her school and life.