Can you try a cocurricular class - karate, dance, arts and crafts, piano ...etc.
Something that would not be a "breeze" to your DD. If it is something that she has to work at it may make her realize that she doesn't "know" everything. I'm suggesting this because in her world she is the brightest or one of the brightest.
I was a straight A student as a child up until 5th grade. I would make the honor roll every year. My principal would call up the honor students to the stage in front of the school. I probably became lax in fifth grde so my grades dropped below honor level. You can imagine how crushed I was when my name was not called.
I am not suggesting "crushing" your daughters feelings, of course - However, if she starts something that would be a challenge and not a "walk in the park". It may be just enough for her to realize that not everything comes naturally to her. In the end she may stop being "bossy" and learned something she can carry with her in life.
Again, this is just one method that may work. It is difficult to say when I haven't spent time with your child. In all honesty she may just grow out of it - or it may just tone down a bit. One never knows - but it may be worth trying.
Hope this has helped
