How do I get my overachieving nine-year-old to relax?

My daughter remembered that she forgot to do her homework while brushing her teeth for bed. I said not to worry and that she could do it then. She starting crying and saying that she does everything wrong (her automatic response when anything goes wrong). Two days ago she got an 88 on a math quiz and started crying because she thought she was a failure, even though I told her I was still proud. I have never EVER put any emphasis on her grades, nor have I EVER expected perfection from her. Help!

Dear Mom, You sound like a warm, flexible, and very loving mother.  First, let's be sure it is perfectionism that your nine-year-old is dealing with. Could it be that she fears her teacher's disapproval and anger?  Does her father react when she fails with frustration or disappointment?  Is there peer pressure within her class when other kids ask, "What did you get on the test?"  If the answer to these questions is no then she may be a self-imposed perfectionist.Are there other areas in her life in which she supremely organizes (or attempts to) her environment?  For instance, is her artwork filled with repeated patterns of colors, shapes, and figures?  Does she line things up in categories of color, size, or height?  Does she dress herself neat as a pin, or "without a hair out of place"?The bottom line is your daughter needs empathic narrative from you.  The key is your vocal tone and body language when you say the following.  Be sure to have genuine compassion in your voice.  Say, "You know, Sweetie, I think sometimes it's hard to be you.  You're so hard on yourself.  You don't even give yourself a chance to misstep."  Then, say nothing more.  Watch her to see if your message seeps in.  You should see her relax a bit and take a deep breath which is her way of letting go of some of the anxiety that keeps her wound up tight.  The easier she can be on herself, the more she will be able to tolerate imperfection in others.We can't prevent life's inevitable letdowns and disappointments.  The best we can do is equip our children with coping skills to deal with disappointments.  Each time you let her wrestle with her own self-disapointment you give her an opportunity to grow.  Remind her that no one is perfect.  We all make mistakes.  And, we all need to accept ourselves -- flaws and all!