If a teacher never gives a child above-level work, she's unlikely to realize that he can do above-level work.
It's quite a delicate balance between advocating hard enough to make a difference and yet not being either too "pushy" or too wimpy. Especially at the beginning of the year, it's a real challenge.
I'm lousy at it, and others here are real pros, so I won't say much. The only thing I will tell you is that I made the decision early on that if it came down to my son--a normally VERY well-behaved kid who was acting out because he was so miserable in 1st grade and who was beginning to think badly of himself--becoming "that kid" or my becoming "that parent," then I was going to bear the brunt of the teacher's judgement. I could handle it; my son shouldn't have to.
I think most of us are nice people who don't like to make waves or be thought of badly by others. Sometimes you can advocate without that sort of problem, and hurray for that! But not always. So while you're calm, I think it's smart to consider what lengths you're willing to go to if you absolutely must and what your limits are. Prioritize.
Not much help, I know...Sorry! But I wish you well!